Let me try this in a little more "politically correct"manner--something I'm not always good at:
Go find an experienced instructor. By that, I mean someone who's worked airplanes in confined areas. Someone who has experience with those modifications and your airplane type would also be in order.
I can tell you that holding full nose up elevator till the airplane lifts off is NOT the best STOL approach for a C-172 with those mods, and yes, I've flown that kind of setup. The Sportsman cuff does not like really high deck angles. It won't do anything ugly at very high deck angles, but it won't lift as well, which is what you need it to do. It works largely because it adds a lot of wing area (and the camber changes,of course). Note that I'm talking DECK ANGLE here, not alpha.
If you're banging the tail, there are a couple issues: First, it is entirely possible to damage the tail doing this. It is also possible to jam some things in the tail, causing control problems--not good. Finally, doing so puts the wing at such a high angle of attack that I'm betting it's well above critical AOA while on the ground. Now, you're rolling along, eating up runway, while the wing makes all sorts of aerodynamic drag and darn little lift. Again, not good. Especially on a short runway.
Now, as to whether you should stop, apply brakes, then full power, etc, or do a rolling takeoff: I would almost (always gotta have those weasel words) NEVER stop on an off airport unprepared surface then use full power with brakes applied, due to the potential for prop damage. Even if you have a very narrow strip, and turning around is a bit tight, you still have to turn around and face the takeoff run.
Unless you are turning around, then shutting down, and pushing the airplane BACK further to give you more takeoff area (which would be a holy crap kinda deal) you will still benefit from keeping it rolling as you complete the turn, accelerating away. As Tim said, even if you start the takeoff with 2 kt forward speed, that's 2 kts you don't have to accelerate to. Get the thing configured for takeoff as you back taxi, and as you near completion of your turn to the takeoff heading, come in smoothly with full power and STAY OFF THE BRAKES. It is REALLY easy in these airplanes to ride the brakes a bit without really realizing it. Keep your feet flat on the floor once you start the t/o run, with just the tips of your toes on the bottom of the rudder pedals. I think you'll find that your performance will be better, and you'll really be doing your prop a favor.
Now, as to getting used to the Sportsman/VG combo--I really, really, really strongly suggest getting some dual instruction with someone who has experience there.
Test pilots generally get paid a LOT more money that most of us do. There's a reason for that.