I've had the ZDZ50, DA50 and Taurus 52 in my hand... for narrow cowls the DA appears to be the smallest... the Taurus is shoter but has a side mount carb...

the ZDZ isn't much bigger than the others...

So I guess I'd say the DA-50 (and any other rear carb) would be a safe bet... AS LONG AS you have the space lengthwise... if not you need the ability to put a whole in the firewall for the carb to set back in...

Also Brison has a new Revolution 50 that has a rear carb and LOOKS alot like a glow motor...

Check it out too... they are all priced about the same.