I've built a 125% Spit recently, It fly's ok but needed almost full throttle to stay in the air, Power system was out of a heavier high wing model, I have also built a 109% and that flys great and will fly far slower than the 125%, which is strange because it weighs about 50g more than the 125% Spit
Post some pictures and Video here
https://forum.flitetest.com/index.php?threads/ft-spitfire-build.4288/page-75 if you can, interested to see how you get on, hopefully you can give me some tips so i can get mine flying better
Quick video of my re-maiden