Originally Posted by zero3803
being a bit leggy, I find myself having to push up and back to free my knees easily from the thigh braces
Unless you can move the seat back (and decide that you should to get the boat trimmed properly) I wouldn't expect that part to change when you're underwater. Being upside down definitely makes it easier to get out, but some of us with long legs just can't get our knees out of some boats without moving our hips back, and the back part usually requires a few inches of up as well. For several years I paddled an I:3, which evolved from the Inazones. One of those evolutions is a bigger cockpit, but I still can't get my knees out of the I:3.
I'll agree that *really* wanting to get out of the boat may make it easier, but you definitely don't want to panic. Being calm enough to loosen the backband will give you a little more room to move back. After you're comfortable doing it in calm water, practice on some moving water, but pick a spot that's not full of rocks. Being comfortable with it and knowing it won't be a problem is the best thing you can do to make sure you don't panic.
The good news is that you should probably get out about the way I'm guessing you do now, anyway. Tuck as tightly as you can, pull the grab loop (being careful not to sit up), slide your butt back, and either continue sliding the boat down your legs, or roll forward as you come out of the boat. In a pool, or someplace where you're absolutely positive there are no rocks you can just push yourself straight "up" from the seat, but in the real world you want to be sure to protect your head and face. Holding the tuck and sliding the boat off or rolling forward from the cockpit will keep your face, and the rest of your upper body, fairly close to the surface.
Lastly, in case you haven't already considered it I'll warn you that having to slide up and back to get your legs out could be a concern in some pins. If water pressure makes it too hard to push up and back with your arms being able to get your feet on the cockpit rim, or even above it, could be very useful.