I designed the and kitted Primo Grande back in 2014. All the ones I built used a DLE55. If you keep it light (< 17lbs is great) the 55 will do fine. I always used a Fiji 16oz water bottle tank with a 2 line setup. Had a T in the line running to the carb for fueling. BTW, prototype #1 and production #1 were sold to the same guy in our club and both are still flying!