My car had 17 all round and changed to 18. Running Goodyears. Can't rotate the wheels now, front and rear different sizes. And have a space saver in the boot as my cars a commuter. Still managed to get two soft bags in there for holiday, obviously no roof down.
Most punctures, like the one i have now are slow to release air and have known about it for a month or so now. Just keep topping up as i am about to fit two new rears before mot, just trying to get the most out of them. The tyre fitter i go to suggested not to use the goo in the can, as it makes a right mess for them to clean up.