Just completed my Rascal 110 with an ASP fs180.It was the only glow motor with a nice muffler and straightforward install. You have to recess the firewall for the saito150 and 180.
Getting the CG at the recommended spot was a little tricky as it tended to be a wee bit tail heavy.I used a 9155 for the elevator and beefed up the linkage, didn't like the supplied stuff.I reckon an engine about 1200gm and above would make balancing much easier. A gas engine would be good although the carb sticking out would look a bit out of place in a pretty plane.