I have now converted about 30~40 engines in total, 10 or so for myself, the rest for others, ranging from .30 to 4.00, fourstroke and twostroke, NONE of them use a fuel pump.
All my engines still use the carb it came with from the factory.

EDIT: way back when I started converting glow engines to gas, I used to modify the original glow carburettor's fuel linearity, which yielded very usable but also fairly "dirty" running engines (lots of black exhaust residue) but since about 5 or 6 years, I started using the solenoids as utilized in the Stihl M-tronic line, and some custom made electronics to control the mixture.
One size fits all, and that works well for most of them, from .30 to 4.00 cu.in.