Welcome aboard and congrats on a nice car. Wheels are usually 15 x 7.5" front and 15 x 9.5" rear. There were quite a few tire and wheel sizes that fit though. Look on the wheel spokes for identifying letters and numbers. I sent you a PM for your e-mail address.
Plenty of info and recommendations on here about tires. I like the Goodyear Billboards for the money and performance. They say not for highway use though some companies insure them. I would scratch BFG's off my list of options. A low profile floor jack helps but you have to come in diagonally by the
oil cooler scoop on the front and pickup the front frame cross member. Rear you should be able to come straight in and pick it up under the diff or the cross member ahead of it.
Fuel tanks were typically 67-69 Camaro with some mods.