To answer the OP's question, you want to meld Savage Aim (crit) materia into it.

Savage Aim III
Savage Aim III
Savage Aim III
Savage Aim III
Savage Aim II

This will give you 27 (max) total. Combined with the inherent max int/vit/acc and decent det values already on the piece, it makes it better than anything short of i90, and almost as good as the Allagan body. (if current theories on smn stat weights can be believed)