what effect would switching a 10/6 prop to a 11/7 have on flight characterisitcs? my guess is none!(keeping engine the same,, say..46 2c) in theory, you should get better climb, and higher top end speed,
Any body seen any float kits for sale in the UK I have seen in the States a set of Carl Goldberg floats as in this link http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXFPX7&P=0 or a set of great planes floats these are to go on my Piper Cub 72 inch span