I think you've got it backwards. If the plane balances at 3 1/2 inches and it is supposed to be 4 3/8 then the nose is too heavy. Look at it this way...if you had it balanced at 4 3/8 inch and wanted to balance it at 3 1/2 inch, what would you have to do? You'd have to add nose weight to move the CG forward.

Conversely, if it is at 3 1/2 inches and you want to move it back to 4 3/8ths, then you would have to add tail weight. Or reduce the weight in the nose. Does that make sense?

Jim