Rick,
To answer your question directly, no the Spitfire is not too big. One very competitive Expert who flew my AT36 on a Brodak P-40 said is has enough power to fly his 60-size plane, and told me whatever I do, never let the engine out of my hands.
The wing on the Spitfire is low. Depending on how well you want it to fly, and if you are a bit adventurous as a builder, adding some dihedral is likely to improve the vertical CG location and the already good looks of the plane.