Troubleshooting and the forward tongue position

Before I get into today's journey, I feel the need to mention that yesterday morning, I casually practiced some of the highest passages from I Puritani, and I felt fantastic!  I even attempted the high F at the end of Credeasi Misera with some success.  I tried something new - usually I tried singing "l'ire frenate" in the phrase going up to the B-flat and A-flat, and then I would just start on the high F with the word "poscia."  But instead, this time, I tried "l'ire frena-a-TE" with the final syllable of "frenate" on the high F.  I expected this to be all the more impossible because the F was coming at the middle/end of an ascending phrase - but it actually turned out more successful!  I don't totally love the sound I'm making up there, and I kind of feel like it might be a sort of reinforced falsetto - but it's certainly respectable, and I would be quite happy to do it in performance like that.  After all, half of the tenors who attempt the high F do it in some sort of heady mix/reinforced falsetto.  There are only a few - Brownlee, Kunde, Matteuzzi - who do a really convincing high F that sounds connected to the rest of the voice.  Anyhow, I achieved success with the F and with the preceding D-flat.  I felt like the D-flat particularly went into a narrow, yet full place, in which it felt both powerful and in control.  The odd thing about high notes for me is that when I really do them well, it feels as though they are going to be impossible.  My best high notes usually occur when my voice feels a little bit "low" and robust - and I will hit the preceding note, perhaps an A-flat or B-flat, and that note will feel like it must be the absolute top of my range.  I will feel as though I am at a ceiling, and I will think that ascending to the D-flat would be impossible from this place - and then it just comes out!  It's the oddest thing, and I have trouble describing the sensation.  Because when I say I feel like I am at a ceiling, I don't mean that I'm struggling or that the larynx is high - it just doesn't feel like I am singing in a high position.
Anyhow - that was yesterday.  Today, I wasn't feeling quite as wonderful vocally - yesterday was a nice "fluke" that I can hopefully eventually turn into habit.  Oftentimes, I feel that vocal development works thus: A teacher will be trying to get you to do something, and you can't quite do it or figure it out.  You try really hard with seemingly little success.  Then there might be a fluke one time when it works, and it feels so good, but then you can't replicate it, so you wonder if it was just luck, or if you just imagined it.  Then you move on and work on other things and forget about that one thing and then a year down the line, you are singing better in general and then suddenly it strikes you - "this is what my teacher meant a year ago!"  But at this point you are doing it consistently, and you never even realized you had figured it out.
So today I was experiencing some of my usual issues of having trouble connecting immediately to my support - my voice felt a little thin and pressed at the top - but when I tried to take the "pressed" feeling off by giving a little more warmth to the tone, it just felt loose and overblown.  Sometimes when I experience this sort of issue - a general sense of weakness, I try to troubleshoot by thinking about the breath or the body or keeping my rib cage open - and these direct approaches usually don't help.  Today what did help was some experimentation with tongue position.  It's amazing how something as physically small as the position of the tongue in the mouth, or the position of the jaw, or the larynx, can so hugely affect the sensation of resistance and support.  I think it has more to do with the fact that removing compensatory tensions forces the body to support deeply - but I don't sense it as a deep body/torso/lungs issue, I sense it as a vocal tract issue.  Now - I don't want anyone who reads this to walk away thinking that I advocate controlling the tongue, or putting it in some particular forward position.  There is no one size fits all.  I just happened, at the time, to be experiencing a tongue that was dipping down and back on the left side, so thinking forward with the tongue helped me.  Now - it is important to note that I never once attempted to stick my tongue in a position and force a vowel through that position.  The true integrity of the vowel always comes first.  Really, I was just releasing the tongue's false dampening effect in order utter a true vowel.  But for me this has to be a conscious effort.  The thing about the tongue is that it is very difficult to feel.  The changes are subtle, and oftentimes I can think that I am very deliberately keeping my tongue released forward - but unconsciously, through the formation of vowels and through my habits, the back of the tongue is dipping low.  Today, the sensation that helped me achieve a properly behaving tongue was the sensation that the tongue was fairly narrow in my mouth.  This does not mean that I was bunching it up - it's just that my perception of the tongue when it dipping down on the left side is a sensation of the tongue being wide and flat on that side.  So I thought of a narrow tongue down the center of my mouth, and I sang an [o] vowel with this thought in mind.  The [o] really focused beautifully, and the sound was somewhat baritonal, and lent the support nad resistance I was looking for!
Now, there are other instances when I will specifically think of a wide tongue.  It just depends on what issues I am having.  It is very important, I think, not to make rules for yourself while singing.  Singing is an act of constant experimentation, and you are cutting yourself off from so many possibilities if you decide "the tongue should always be forward" or "I should always breath through my nose" etc.  There are things I didn't discover and achieve in my own voice for years because someone had hammered unspoken rules into my head like "don't push" or "lighten up on the top."  Indeed, in my undergrad training, there was a widespread fear of "pushing" and "over-singing" and students and faculty alike seemed to equate light and bright with "good singing" and dark or heavy with "bad/dangerous singing."  This was so damaging to me.  It took me so long to discover my true tenor voice because I thought tenors were supposed to sound light and bright and forward and reedy - so it never occured to me that exploring the natural slightly deeper color of my voice could actually help me unlock my high notes!