OK, I was able to find most instances in the code that refers to the names, here's the one that allows you to increase letters in the "Please enter a name" screen:
Change character XX's name to YY
(gen. act. 7F)
C0/A03A: 20AD9D JSR $9DAD
C0/A03D: A906 LDA #$06
C0/A03F: 8D0242 STA $4202
C0/A042: A5EC LDA $EC
C0/A044: 8D0342 STA $4203
C0/A047: EA NOP
C0/A048: EA NOP
C0/A049: EA NOP
C0/A04A: AE1642 LDX $4216
C0/A04D: BFC078C4 LDA $C478C0,X
C0/A051: 990216 STA $1602,Y
C0/A054: BFC178C4 LDA $C478C1,X
C0/A058: 990316 STA $1603,Y
C0/A05B: BFC278C4 LDA $C478C2,X
C0/A05F: 990416 STA $1604,Y
C0/A062: BFC378C4 LDA $C478C3,X
C0/A066: 990516 STA $1605,Y
C0/A069: BFC478C4 LDA $C478C4,X
C0/A06D: 990616 STA $1606,Y
C0/A070: BFC578C4 LDA $C478C5,X
C0/A074: 990716 STA $1607,Y
C0/A077: A903 LDA #$03
C0/A079: 4C5C9B JMP $9B5C
Initially I want the character names to be 8 letters long, and I figured I need to add a couple of STA's followed by LDA's in the code up above.
But my problem is with the actual menu; when I change all the associated code, here's what happens: Naming screen is ok (cursor gets crazy), and when accessing the menu, the character's level becomes crazy, and one of the letters from the name seems to be erased.
Sounds like some variable is overflowing, but I'm not sure. Any ideas?