Michael,
I think we are talking about the same thing, in a different way.
I am talking about training individual moves, all the moves I can but some will be more prevelant and easier for me to learn, until they are my bodies natural mechanics, and then they become incorporated into what I would use in an actual combat situation. In other words, how I would react to combat.
Slavishly conforming to the movements in the Wu 108 or the YCF 103 postures would get your butt kicked pretty fast in reality. They're guides to possible defenses, not the real way you would defend yourself in combat every time. The postures give you the moves your body needs, in general, to defend itself, but I don't think they were ever intended to be actual combat moves, to be used during combat to the exclusion of anything else.
What I was taught to do was to learn the movements from the forms as well and as deeply as I could, so they would occur without conscious thought. Only then are they really part of your "style" of self defense.
You will not do a "right ward off" clinically perfectly to defend against incoming force. You have to adjust the height of your arms, your waist, your legs, your stance, everything, to accept and redirect the incoming force as it has been manifested by your opponent THIS time. Your movements may be very close to "right ward off" but will not be a clinically correct version of it.
Will not be, can not be in order to be effective in real combat. You must adjust your movements to that of your opponent, so every combat movement will be different and may have, in fact almost always will have, no discernable relationship to any of the static postures from the form.
I was also taught the painstakingly correct forms for push hands as a beginning exercise in self defense, also not to be slavishly followed in combat. One handed, two handed, chain step, nine palace step, da lu, all are push hands, all are effective in helping to train you for combat. However, for real combat readiness training, we learned to spar "free style".
That's where we were taught to "fight" in Wu style training.
We would pair off into groups of two people. One would agree to be the antagonist, the other the defender. The antagonist attacked the defender in any way that seemed appropriate, bum rushing, round house punch throwing, straight jabs, kicks, all kinds of punches, whatever looked like it might work and only crippling and killing blows were not allowed. The defenders, of course, defended themselves.
It is never pretty, not choreographed and you wind up doing things that you have no idea where they came from to defend yourself.
You also learn VERY fast NOT to rely on any "form" or "posture" for defending yourself against an attacker. If you try to emulate the forms exactly like you practice them, you'll be getting a beating of biblical proportions in no time.
For one thing, if you take the time to think "I need to move my hand up to the left a bit, now I step, now I turn my waist this way...", you're dead before you started.
Your movements need to be without thought, yet still retain the elements of Taiji. It does not matter if you use the upper body posture for "raise hands" and the foot movements from "snake creeps down". It doesn't even matter if you use the upper body movements from Wu style "needle at sea bottom" and the foot work and tantien turn from YCF style "diagonal flying", as long as what you do accepts and redirects the incoming force being applied against you, it's correct. Heck, I would often regress to the forms taught to me during my sojourn into Tae Kwon Do, all those moons ago, if necessary during free style. As long as it's applied with internal intent and your movements succeed in defending you from your attacker, that's all that really matters.
Once you have reached this stage of moving yourself in technically correct ways, but not adhering to any actual form movement to achieve your goal of defense, then, at least in the opinion of my former Masters and Sifu's, you have begun to actually DO Taijiquan instead of merely dancing around to the form.
I reached that state a long, long time ago in Wu style. I, unfortunately for me, let myself slide into the realm of not being able to do that as well as I used to.
Now I am working towards the goal of re-attaining my former level of skill in Wu style techniques, AND being able to reach that level with YCF style techniques as well.
So what I am refering to as "my style" will be revealed during free style sparring. When I will have incorporated the new ways of moving and defending myself learned from YCF style into my personal defense repetoir seemlessly enough to be able to use them in actual combat.
Long winded, to be sure. But then again, I usually am.

Time to go do a form. 13 posture, I think.