I can imagine 2 ways:
1) Freeze a character's XP at 99 and go kill something - you'll get several level-ups whenever you gain XP. Note that characters with quest-related rank-ups (Wil, Aht, Suina, Uya and Melodiana) won't be able to advance past those ranks.
2) Estimate the stats by their caps - i.e. set the stats at 3/4 the cap or around that. However, if you're going to just overwrite levels and stats to desired values, then you will skip all rank-ups and their bonuses.
Also, I can see a problem here: if you wiped your save, then how are you going to get to NG+?
I guess I could send you my old save from 2nd playthrough. Will that do?
P.S. I have restarted from scratch twice already, last time a few days ago (although I didn't touch the game for several months before that). The old save I mentioned as actually from my 1st attempt at the game - I seemingly lost it in a disk failure and started anew, but much later discovered that I had a backup
