Would need an example of what you want to change, but text format is usually independent of font size.
The only difference is that on NES, with 8x16 characters, they could be stored relative to the order in memory, or according to the tile number.
Like say tiles 0x20, 21, 22, etc. were the top of A, B, C.. and 0x30, 31, 32, etc. were the bottom of A, B, C, they might've stored the text as A=10 (since 0x20 would be the second row of 8x16 characters) or they might've stored it as A=20 since that's the tile number of the top half. You'd have to try both (unless you know enough ASM to debug the print routine to find out for sure).