I have built 2 SPADs so far, my first is a Kadet replacement, with a ST90 on it, flies great, knife edge, everything, Second was a SPAD 3D inspired by NovaBill on another forum (search "spad novabill") a hero in my book !
Out of respect for his design, I posted complete detailed plans for my version on my club's web site:
You have to select the "B Spad" selections on the left sidebar.
My Son, the better pilot, has a ball with it, and enjoys it more than his other high performance planes: an Ultimate, an Extra 300, an F18, a Concept 30 helecopter, and a Sukhoi 31 with ST-2300. (most are on the above we site at "Models Page 3")
Check the plans & tell me what you think about them.