P245/60R15 tires. Which would you choose?

I know your car is destined to be a cruiser and all, but here's my opinion;
if you put 245/60s on 7s
your first hurdle is rubbing, and the second is tire pressures.
As to the first, and on the front;
depending on the backspacing, the tire will want to rub on something; Either on the frame in the back, or on the strutrod in the front, or the upper BJ will want to knock your wheelweights off, or if the car is lowered, they might want to rub on the fenders, especially when backing up and turning. So backspace will be very important.
A 245 is only a 245 on a 70% checking rim, which is 6.75rim; rounds to 7inches. But 245mm =9.64 section width on that rim. and the height will be about 60% of that so 5.79 inches. The tread will be about 8 inches..... On a 7" rim the outboard 1/2 inch on either side will not want to sit on the pavement at a "normal" pressure of say 32psi. In fact, it may never wear equally with the rest of the treadface no matter how much you lower the pressure, because those 1/2" per side are outboard of the wheel rim.
Ok that leads to the second hurdle; tire pressures. Say you run 24 psi to get somewhat of an even IR temperature across the face of the tread. You could get away with that on the back, but not on the front. If you try it, it will be fine in a straight line, except for the mushy steering and riverbarge handling, but in the turns, the inertia of the bodyweight will overpower the sidewalls, lift the inboard treads right off the road, and put the outboard sidewall, just 2 plies of it, onto the roadway. At 24psi, this cannot be avoided. So now, you have road hazzards to deal with. Radial tires have no ability to withstand sidewall abuse. And I'm not talking aggressive driving here, just normal everyday cornering. So 24psi is out. In fact the minimum pressure is gonna be about 28 psi. And that is gonna lift the edges.

24psi on the rear will work, I mean besides the floaty ride. But again, when cornering, the rear of the car will sideshift. This causes two things; 1) the rear will tend to oversteer, causing a bit of a surprise to the driver, and again, 2) the sidewalls are gonna want to roll under. It's not quite as pronounced in the back, on account of the rear is lighter, and has not as much inertia.
All in all, you will be rotating the tires more often, and leaving more rubber on the road than is necessary, causing you to replace your tires more often.
but hang on
there is no correlation between treadwidth and section width, nor any specification regarding treadwidth of any kind.
So just because I guessed at your 245 having a treadwith of 8 inches, does not make it so. The manufacturer is free to install any width tread on his tire that he wants to. So maybe, just maybe, you can find a 245 with a 7" tread, then yur good to go. And that is where a cheap tire is likely to to get at least part of it's cheapness. So now you have a fat section 245 balancing on a narrow 7inch tread, and maybe you can run that at 30 psi; and so everything is golden. Well except for your contact patches..... since those are now 225mm sized, you might as well just put 225s on those 7s in the first place, and run those at 30ish psi, all problems solved...... depending on your backspaces..
And that's my opinion.

The 70%checking rim for a 225 is 6.2; rounds to 6 inchs. Meaning that a 225 tire installed on a 6" rim will have a sidewall section-width of somewhere between around 225 +/- 5mm.
But that does not mean you have to or even want to, run that 225 on a 6" rim. That 6incher is already .2 less than what the formula spits out, and at 7 inches the ratio is just 79%, IMO a much better number. ( I like 85%)
Yes you could run a 235 on a 7"rim for a ratio of 75.7%, and on your cruiser, you should be able to find a pressure she likes. But in my experience 235s like closer to an 8 incher (86.5%); I think mine are on 7.75s (83.8%) and they like 28/29, on the front, holding up an aluminum headed 367, with battery in trunk.

The bottom line is this;
IMO;
a 7 inch rim wants ; (7/79%) x25.4=225mm
an 8incher wants..... (8/.81) x25.4=251mm
a 9 will like ............. (9/.83) x25.4=275mm
a 10 might like ...... (10/.85) x25.4=299mm
All are +/- 5mm
all work at 50/60% profiles; taller tires will put up with more narrow rims.