rim width?

235s are fine on a 7 or 8 inch. On my station wagons (have 3) I run 235/75/15s on a 7" rim , 235/70/15s on a 8" rim, and 235/55/17s on a 8.5" rim and they all work well.

295s would be a min of 8 for sure but prob want wider...

295 on an 8" rim I feel is too wide a tire. I put 295's on my marauder in the back and widened my rims to 9.5". If you are going to piddle around an 8" would work but if your going to race (1/4 mile) or do spirited driving I'd think otherwise.

this is goin to be a cruiser car for me and the wife, no drag racing, lol. Thanks!

295s fit nicely on a 10 inch rim. Problem is 10 inch rim is a tight fit on an early Cougar. 67s and 68s have a little less room than a 69 and 70. You didn't specify which year car you have.

1969' base

What offset on the rims?

A couple of guys have fitted 10s on the rear of a 69 or 70. Zogman comes to mind right off the bat. The key is backspacing. I don't know the exact number. But it was somewhere in the 5.5 inches or even more. I've even seen guys with with as much as 6 inches of backspacing. Problem then lies in whether the wheel of choice is available in that configuration, or if it can be custom ordered.

If you can custom order something, be prepared to wait. Even the big name wheel makers wait until they get a whole slew of custom orders before they shut down regular production and tool up for the custom orders. I waited 8 weeks for my rears and 10 weeks for my fronts. I ordered them at different times during different portions of my build.