Not sure what help I can give on account of the methanol fuels we run down here in our burning climate...........Anyway, the slide numbers on the racing carb's are generally in 32 th's of an inch so just check that the slide does in fact have a cut away 1/4" in height. On petrol type fuels I would think a cut away 1/4 or slightly more would be a good start. We had genuine 32 mm TT's on the racer which is 1 1/4" and that bike ran very well, good power and torque. On my current 500 racer the Amal Mk 2 smoothbore carb was set up too rich, and the engine would not come back on power cleanly out of corners. I modified the slide as per normal, opening up the cut away (cant remember exactly how much) perhaps a mm or so, and after a test ride around the block, the engine pulled cleanly out of any corner. It is actually better than i had the twin racer set up........Unfortunately I never got the chance to get the twin spot on as i don't have it anymore. But a slightly larger cut away on both carb's would have cleaned it up that bit more. I will most likely be running an 1 1/2" GP Amal on the racer with the new Comet engine that is being installed/ built as we speak. The beauty of these carb's is they are ideal for Methanol fuels due to the large 302 amal float bowls they run......Other more modern carb's are great but their fuel bowls struggle to deliver enough fuel to the main jets. Good luck with it all.........