I just remembered something about Supertigers. The two screws that adjust the angle of the nipple to the carburetor. Mark your stock setting and then play around with that. That should fix you low end. I have had a lot of experience with Supertigers years ago and moving that spray bar around will make a big difference in throttle responce. I also heard but have not tried a trick I heard of a few months ago about Supertigers. Put a piece of fuel line on the carb nipple and blow through it and have the two screws loose on the spray bar. It should be less restrictive at a certain spot and that spot is where the spray bar hole is shooting straight into the crankshaft. It is similiar to setting up your low end needle by blowing though the nipple and adjusting the lowspeed needle.