I am currently flying a Fun-51 and it flies quite well...
However....
There is not one dimension on my plane that is the same as the kit design. I had to change EVERYTHING!!!! My flying buddies in NVCL kept telling me: "you coulda designed and built something really nice in the time you spent on that thing! Maybe two!" And they were right.
Only do this if you like challenges.
I also modified a Sig Fazer years ago. Not quite as bad to modify, but still....
Here's 2 hints:
One - get a couple of bottles of "white-out" so you can white out the lines on the plans and then re-draw them. (The guys in our club thought it was hilarious to roll out plans and watch the white-out pop off.) The moments are all wrong on these things. The wings not tapered, and the elevator is just wrong.
Two - CA the rear punch-outs in the ribs so you can re-cut and taper the wing starting at the spar and trimming at the trailing edge. Otherwise you build a barn-door.
Here's your challenge goal: use as much of the wood in the box that you can and only add wood that isn't there. No fair substituting wood out for lighter stuff. Of course, the plane will be heavy and would have flown better if you had substituted wood. But then, you should have built from scratch and used a design that wasn't a POC.
Just saying

Scott