REAR Weld Draglite 15x10" what size tire?

I am thinking about a 295/50/15 Firestone Firehawk Indy 500....these will be for street use only as i have another set of 15x10" with M/T et streets on them....what do you guys think?

I want these tires to actually last :-) 295? 315? list me the best size you think for a rear 15x10" Weld Draglite.

anyone?