The ratio is usually 3:1, so every ounce you take out of the tail is 3 ounces of nose weight you won't need to balance it.

Dremel some weight out of the tail.
Use lighter control horns on the tail surfaces. Cut excess bolts and screws off the controls horns. Once the horn is bolted on, any excess bolt hanging out is just weight.
Use lighter control rods in the back. Instead of using 4-40 rods, use 2-56 rods and brace them up with small pieces of balsa. Lighter than the 4-40 rod but also more work.
Get a lighter tailwheel assembly.