Are you using the 90 degree intake horn? If not, get one and plumb the diaphragm vent tube to it.

All gasser carbs behave the same way. The low end mixture screw is effective over the entire throttle range. The high end mixture screw is effective only above half throttle. Adjust the low end mixture for snappy acceleration from idle to 1/3rd throttle. Then adjust the high end screw for max rpm at full throttle. Make sure the high end mixture is on the rich side of max rpm. Test fly and listen to the engine in the verticals at full throttle. If it sags or slows down richen the high end mixture 1/8th turn and fly again...repeat until it pulls hardest in the verticals at full throttle. Then fly it around straight and level at various throttle settings. If it is rich and burbling excessively, note your corresponding throttle position. If it burbles at 1/3rd throttle you need to lean the low end mixture. If it only burbles above 1/2 throttle, then you need to lean the high end slightly.