Need New Tires - 2001 TRX350FE

Need to replace tires on my 'ol steed. Original tire size was 24x8x12 and 24x9x11. I was thinking about a 25" tire, but wanted to know if and how much wider I can go on rears? The majority of "sets" don't match that size. Is there a limit or suggestion that somebody can provide on what 25" would be a good fit? Mostly run in woods and muck.

Thanks in advance,

Steve