Hi Xymotic, it may be too late for you at this point, but might help others. The arrangement of mounting the pulley right on the flywheel will place side loads on the engine
bearings. This is ok for light loads, but if you draw much more than 2-3 HP from that arrangement, your loads will be more than the engine
was designed for - of course it will work just fine for a while but could result in premature bearing failure. Hayes Couplings makes a nice bearing supported shaft that bolts on and takes the side load issue away. It take a bit more space and adds a bit more weight but in theory, increase the longevity of the engine.