The problem with shortening the tail to use less lead in the nose is that you also lose out on the authourity of the tail over the plane so you end up with less control response and have to move the CG even MORE ahead because the NP is pushed forward by the shorter tail.

The most effective way to use less lead in a model is to simply make the tail lighter. It means modifying the plans to use less material or switch to a higher strength material which you can use more sparingly. But either way if the model flys well now then shortening the tail will make it fly less nicely.

The only reason to shorten the tail would be if it was already extremely long. But if you're modeling the look and feel of it on present aerobatic platforms then I doubt if you made it overly out of proportion in that way. So that leaves you with either adding weight to the nose by some means or making the tail lighter.

I don't see reducing the size of the overall model as viable unless you can ensure that you can reasonably build it with the original engine down to a suitable and acceptable wing loading.