I have tried the carb for the DLE 20 and 30 on this engine and both fit. The needles are a bit sensitive with the 30 carb so I'd recommend the 20 carb. My RCGF 15 was a poor runner til I installed a Bowman ring. That made it a nice engine with decent power and would hand-start. The reed mod is always a good idea and a great learning experience. After doing it to one engine, I now carry out the same steps on all new engines or whenever I have the opportunity to remove an engine from an airframe when other work is required.
Hope this helps.