i've been experimenting as well... not great areas around here to test out....
if i set too high, i spin/ traction control kicks in and i bog, garbage launch. if i set to low, it just bogs by itself. IDEALLY you would launch with no TC of course but i dont think launch control works with no TC does it? if so, i imagine you'd spin bad
i'm using stock tire pressure when testing out..... and i'm hitting a 3.8 0-60, best i can do so far