I would lean toward bigger, rather than smaller, with an electric
. I figure that way, if you need the power, you got it. The bigger motor
won't use much more juice than the smaller one with the same load. Remember, it doesn't have to be 12v, either. Three group 24's in series will do about the same work as the same batteries in parallel.
Yes, gasoline outboards are more long-legged for the same weight vs an electric
system, but for a dinghy
I wouldn't be all that concerned. Remember, you can always row if your batts are down.
Either way, be aware that both electrics and gas outboards are prime targets for thieves. Just sayin'.