having played on a lot of sites, i think it is highly dependant on the game you are playing, to stack off with tp/tk(gk)

I do it constantly at tribeca, to a large extent in prima games yet in a stars game even at 50nl i would be MUCH more selective.

And thats before we get into the scenarios/math or the wheres and whens and whys etc concerning the stacking off of a one pair hand.