Hi goirish
I have built and flown two types of pusher Canards over a period of 7-8 years, using OS46FX and AX engines and APC pusher props. An interesting point is that the engines tend to overheat while you are tuning them on the ground. It took me a while to realize that. Once I learned that feature, I replace the pusher prop with an identical "standard" prop and do all of the tuning. Then I put on the pusher prop and take off. I mount the fuel tank in the conventional location as close the the engine as possible, and then use a very small second tank much closer the the engine. The pluming from the muffler to the carb inlet is all in series. In this way there is never any hesitation. I like to be in the air withing 20 seconds of starting the engine to prevent overheating.