Hope this helps:
https://www.willtheyfit.com/index.ph...0-5&offset2=40
This says that your ride height will increase by ~0.58" (and arch gap loss of same amount) going with 30 profile. As far as running into rubbing issues, I can't comment on that, I went with 295/25/21 myself. Other sizes in 21's were difficult to find.
IIRC, the 30 profile is a ratio of the tire width. Being that 295 are wide, going to 30 will be a noticeable increase from 25. I believe 295/25/21 are closest to OEM spec. I would try a 275 or 285 if you want 30.