I got this tip from a guy that works with engines of racing beetles to prevent carburetor flooding, you drill a hole on the side of the float bowl just a bit above the normal fuel level, screw a plug and connect a hose so overfilling fuel simply drops trough the hose to the ground, don't know if this can be done on the mikuni, i guess this is dangerous but maybe the same thing can be done but routing the hose somehow to return the fuel to the gas tank.

I have read on this site that you can add a pressure regulator and lower the pressure after you start a steep climb, i believe this one goes between the fuel pump and the float bowl, no regulator needed on the accel. Pump.