Hi I also have the HH 50cc Twin and have just given it it`s first run which was excellent with a very easy start after the initial choke which seems to want a bit more as the carb is upside down on the twin but once it fired and started to run it was perfect and now I am looking forward to running it in and getting it into one of my Great Planes Christen Eagles.
If your single cylinder engine compares to the twin and I can`t see why it won`t then I think you will be happy and have some money still in the bank.