Decent handling susp setup?
. Back to square one for wheels.
For what you stated as your goals, don't sweat it.
* Put a sway bar on that works with your '74 K-frame and the lower control arms.
That's going to be huge impact on how it feels (both roll and therefore camber control)
* Drop the rear hieght you currently have with the unmodified SS springs. (see post #32 for for some options.) This will help with caster, roll, and reduce the chance of oversteer.
I'm assuming you're going through with these and the bigger t-bars and maybe the better shocks.
Drive it, see how you like it. If you feel its lacking in some area, then make make additional changes. That includes tires.
You don't need the ultimate in stick. You just need decent for a street driver. Yea I know, heresy. You know better than any of us what roads, and conditions you plan to drive on and how hard you're going to push it. I used BFG's radial T/As for a long time and they're an OK al season radial. They will last a long time, and just get harder as they get older. I don't love 'em but for the price, they'll do just about every road type and condition OK. (not great, just OK).
I switched to the Firestone Indy 500s before they stopped making them. Definately a step up in that they are softer, better traction, etc. However they're not made anymore so no more talk about them. I mention them because if you're just looking for all-season tires in a close to stock diameter, there's probably some options besides the ole' BFGs.*
If the roads are really good asphault and you really want that sticktion, then yes the widest offerings will be in the bigger diameters. But you'll still find some offerings from Toyo, Khumo, Hankook in 15" amongst the less considered brands, and if your needs are more toward an all season radial, that opens it up a more. Don't be locked in on a super wide tire if there is a better tire in close to stock diameter. I've run 205 and 215 and they're fine for almost everything except autocross. (I use a dedicated tire for autocrossing although I use to occasionally run the radial T/As in the rain, but even then they weren't as good as a semi-treaded race tire).
*for example I was just looking for modern snow tire to put on the spare 14x6 and 7" slots I have. Tire-r*ck didn't show much other than some very traditional snows; but poking around the web found the Hankook I*pikes, as well as a Cooper snow for those rims.