Conrad, my PBY doesn't have offset motors however its a good idea. I'm only an intermediat pilot, I can take off, fly around, and land, but I don't do aerobatics. Wish I could, but I just don't fly enough to get comfortable doing them.
I usually go to the club meetings, but not all the time. I hope to meet you too. R/C model airplanes is a wonderful hobby, one can dabble in it, some just go plain nuts with it.
Differential throttle is very effictive at controlling a water plane in water without a rudder. Mike McDougall did a review on the new Electrifly Widgeon G-44 in Aircraft-Exotic and Special Interest/Waterplanes. Scroll a ways down on the Homepage.He goes by the handle Kingsflyer. There is another thred on the Widgeon and Mike explains how to program differential throttle. I've included a link to that thread. I'm definatly going to do it when I set up my Widgeon. May do it with the PBY too.
You'll have to wade through a few pages to get to it. You MUST HAVE a programmable radio to do it.