Tire size thoughts (17" wheel on dropped '68)

[One Big Rush]

I feel like my tires just aren't big enough, especially on the rear. The truck has been dropped as you can tell. 3"/4" with coils. The tires are 215/60/17 and 235/60/17. I'd really like to go bigger all the way around, perhaps a 245 and 275 set up (both 60's). Unfortunately, there are very few if any options out there that offer both sizes from same make/model. I could mis-match tires and keep my current 235s by moving them to the front. Then buy another brand tire for the rear. I just feel like the rear needs more tire to fill the wheel well better. Thoughts or experiences are welcome and appreciated.