I am Scratch building a 40% Extra 300s. Now my dilema is after jumping into this project I am starting to run out of steam. I have the fuse all framed up and ready to go to the next step.

I have a set of wings and tail feathers that used to belong to a 40% Carden Edge. "May it R.I.P." I am thinking of just using these on my new fuse. I am no Aero Space Engineer, but in looking at the two they are very similar in more way than one.

Should I do this or bite the bullet and make a new set of wings?

As long as you are happy with the "LOOK" the wing will fly fine. It won't care what the fuzz looks like

JUST WATCH OUT FOR THE INCIDENCE. IF YOU HAVE TO CARVE INTO THE FUZ TO MATCH THE PROFILE OF YOUR "EDGE" WING MAKE SURE IT SITS IN THE SAME ANGLE AS YOUR EXTRA'S WING WOULD.
JUST 2 CENTS

You may be on to something here. Seeing if the edge wing would work differently at a lower position. I say do it. I would fly real slow and probably 3d pretty well too. Like what was said above, make sure your incidence is correct, but I think it should work great. Heck, I would do it just because it is different.