they run about 29.5 typically. actually the same for 30/9.50 tires. they all seem to like to round up to the nearest inch when they label tires. if you are concerned, then you could go 235/70x15 tires. a little wider and smaller in diameter.
my ranger had the 3.45 gears but i went to 31" tall tires with future plans to go to 32" tires. i did the re-gear and now cruise comfortably on the freeway in 5th gear even on moderate inclines.
you will notice a little less power , but your clutch should be fine. probably won't spend much time in 5th gear on the highway if you have lots of hills or strong winds where you live. if or when you decide to re-gear, there will be many options for you and i would also consider a locker.
good luck!