If you hand prop an O-540 you are the man!!
I flew a guys J-3. No electrical system so it was always handpropped. He had it down to a science. He'd stand behind the prop on the right at the door. Reach up with one hand a give a little flip and Putta Putta Putta it would be idling. If something went wrong he was behind it so he wouldn't get run over and could just reach in and drag the throttle back or turn the mags off.
A friend has a 180 and first flight each day he hand-props the airplane. He too has it done so it's easy to do -- and he leaves the fuel off just in case -- it will idle long enough to walk around the turn the fuel back on. His reason for hand-propping is that he flies into the bush a lot, he wants to know that he can handprop if there is a battery issue somewhere remote. If he can't he knows he has an issue that he might want to fix before launching off into the wilds of Alaska.
Thankfully, it will be a few years before I have to make that decision.
The range of HP I can use is between 150-260.
The only advantage I would really gain from the higher HP engines is an increase in climb speed as the VnE is 175 mph.
I would have to weight that advantages of fuel consumption over higher horses. I would also like to have the ability to hand prop for the same reasons as your friend. Although there is not nearly as much back-country here in Pennsylvania, this is essentially a STOL bush plane made to carry cargo and I would like to do some travelling to non-typical places with it. I am still considering putting amphibious floats on it or, at the very least, putting the mounts on the frame when I build it in case I choose to do it later.
It's the same reason that I like a vehicle with a manual transmission.
