I assume you're only talking about the rear, right?
if so, they'll fit with the right backspace and as long as you dont go too wide on the tire.
Different rear end housings have different overall widths.I wouldnt just go with a certain backspace because it fit on someone else's car .They may have a different housing than you.
With a ruler and a measuring tape you can check your backspace availability.
remove tire/wheel, hold a metal ruler (or stright edge) horizontal (on its side)accross the hub face ,between the studs, where the back of your wheel would rest.
Then with a measuring tape, measure from that back edge to the nearest contact area (should be the inside edge of the leafspring) This will give you a rough idea.
leave yourself room for your tire bead and tire flex
1"?
example: if you got a measurement of 6.5" from your hub to leafspring contact.
I'd go with 5.50" BS leaving you 1" to account for the tire bead and tire movement.
Keep in mind different tires produce different bead sizes. I run 1/2" clearance between the inside bead of the tire and the leafspring without any problems.
My guess, you should be able to fit
15x10 with 5.5BS on a 295 tire
good luck
I have 17X9.5, 275/40/17 on the rear of mine 4.5 BS I could go 5.5. The tightest spot is at the front and rear of the inner wheelhouse. I don't know if the gig tall 15" tire would fit as well though. My tires are only about 25.5 " tall with not much sidewall buldge. John