Congrats as well on the 54 Hank Aaron...It must took you a ton of searching to find a centered one...i remember when i found mine...they are tough to find. Mine was a PSA 4.5 and your looks just as comparable to it...so if your looking at 'bumping' up, i think its very well possible can be done. Could be a 4, corner wear is what holds it back, especially top/right.
If you need to look at mine, here is a link to it:
http://i1240.photobucket.com/albums/...psc3da1df2.jpg