A 2wd launch will never compare to a 4wd. Unless you spend lot's of money on setup, the 4wd will alway's take the cake.. Even then I still don't think it would be close.
It wil jump all over the place. Just get tie rod sleeve's and braces on your front end. Remove or back off your torsion bar bolts. Start launching at around 1800 rpm and go up from there. You'll know when it's right
I have launched from about 2200 before and it seemed pretty nice, but it staying in 4wd it seems slow to me, but that might just me being inexperienced.
Just keep the tie rod to spindle angle out. Keep the tie rods as level as possible, this will help with the drag link being forced to the frame. I have to lower my front end or I tear the front end up pretty bad, bending brackets and stuff.
It looks like you have all the front end goodies needed for a successful 4x4 launch.
The best way to know if you are going to be safe with the lift on is to look at the tie rods from the front of the truck. If they are anything but pretty close to level, you might have so serious tow problems when you launch.
The Tuff Country 4" lift leaves the tie rods pretty straight out from the center link. Not sure about the fabtech.
Also always make sure that you are completely engaged in 4wd. You probably get away with launching a little higher than a truck with stock tires since the bigger tires will probably kill some of your torque.