Something else you have to consider concerning glow/gas engines for a small model is the extra weight (engine and extra battery pack) and the ''most of the time'' less power of the gas engine. I would say that a 17 to 20cc gas engine is ok for a 60 to 90 SCALE model but if you are in to acrobatic flying it could be a handicap. An other thing is the larger size of the gas engine that often translate in to more cowl cutting depending of the model. And yes a good electric starter with a good battery will start a 17cc easy.