Damien - Go ahead with the 65 - you'll have a ball.
I have an eagle 2, for many years, that I use as my workhorse/testbed. It drops bombs,parachutes, piggybacks gliders, takes photos and also goes on floats. I use it also to run in any new engine, so it's had a variety engine sizes installed, from 40 2 str to 80 4str. This last season I have been flying it regularly with an OS 61 2 str.
This is a great plane and with the big fourstroke you will have an great setup.