14 or 15 inch rim advice

hello. I'm looking to get some steel rims. I want a 7 or 8 inch wide rim either 14 or 15 inch to make my sleeper look stock. These will be for the rear and I will get the same diameter in front but a little narrower. I will get 4.25 to 4.50 back spacing it's a 72 swinger with 8.75 rear small bolt. I have 14 inch rims already and can get 14 x 8 rims made out of two of them for $155 a rim and $35 each shipping from that mr mopar place or get the 15 inch ones from pretty much anywhere that are made in either 7 or 8 inches wide for the rear and 6 inches wide for the front, for about $275 more so not a deal breaking difference, in for a penny in for a pound right? But the difference starts with the tire costs on top of that with the extra rim cost and I want it to look good also. I'm not offsetting the rear springs or anything extreme but am using the xhd rear springs from Mancini. So the question I guess is should I use the 14 or 15 and if so which one and what size tires could I use for the most traction and the best value. I don't mind spending money but not like a fool so want the best reasonable advice about this. Thanks in advance for any common sense answers. Also if anyone needs more info for what I'm trying for just ask I will get back asap. Thanks.
Please don't get the wheels widened!
I'm sure they've gotten better, but the ones I've seen in the past had a lot of runout, were heavy, and took a lot of weight to balance.
IMO you'll be much happier with an "off the shelf" selection.
As far as 14 or 15, with drag slicks we like the 14, 'cause it had more sidewall for the same O.D., felt like it hooked better.