Really need help on another tire/wheel question

[SATX]

Hey everyone. I'm in the middle of a build on a tight budget (isn't everyone?) and a very tight time schedule due to a new job and a move back home to Texas. It's a '67 swb fleetside. It came with 15x8 front and 15x10 rear Convo Pro's. The truck has a 4.11 rear end, and we are putting in a 700R4. To help out the gearing even more, I would like to put as big of a street tire as possible in the rear.

The rear was tubbed by the PO, so it will hold a lot of rubber. 295/50/15's will fit fine, but a taller tire would be nice. I have used the search feature extensively on the forum. I see mention of 285/70/15's and 295/60/15's. I can't seem to find these sizes. 275/60/15 also seems to be a popular size, but the tire sites all recommend it for a 7.5" to 9.5" rim. Will this size look alright on a 10" wide rim?

Thanks in advance for your help.