downunder

That Pathfinder should be fine, it's got reasonable wing area. It seems to have a wire pushrod for the elevators with a guide half way along which may keep it from bending on up elevator but I'd suggest a carbon fibre pushrod. Go to an archery shop and have a look at some of their aluminium cored CF shafts, they're surprisingly cheap and work great. I'd also suggest using an RC clunk tank which can easily be set up as a Uniflow if you prefer. There's one brand called IM that I'm using on a profile model which is perfect because it's got a taper that's wider at the back when laid flat against a profile fus. This means that the last drops of fuel go to the outside rear edge so the clunk picks up everything.