boofhead,
I have started a Beaver on floats following an issue with the starter switch. I stood on the cockpit steps on the starboard float and held onto the upper air inlet with my left hand - I was nicely balanced and secure, my arm naturally swung clear of the prop arc, and I could see the throttle. With a radial you get a good choice of compressions to start on - very handy considering the limited propeller arc within comfortable reach to work with.
One of the beauties of the 985 is that a gentle pull will start them once you get the mixture correct, and when they do start it is a very gradual acceleration to idle.
Floatplanes start moving forward as soon as the engine fires, however the "ground" does travels with you so you can climb back on board easily.
W