That sounds like you have it set up nicely, are you sure you don't have a plugged main jet?
If not it's already been said; back to the TBS needles and the 160 jets.
Mines been running fine with the 150s and Thruxton needles. Some seem to like the Thrux needles, some don't. They are a lot richer in the mid throttle, and maybe the 145s aren't getting enough gas to them bigger cylinders at full throttle.
You could play with the float levels, the higher the floats the fuller the bowls the more available gas for the carbs to suck out.
A plug check will tell you what's going on in there. When it stalls, pull the plugs and see what's happenin in the cylinders.
