I'm not sure what pressure fitting is, but I cut the 8 gauge? plastic to size and used contact cement to hold the center and outside to the wheel. I thought I would have to add cement to the spokes too, but the plastic seems strong and taut enough to go as it is. Brakes pads won't work of course, so coaster or disc/drum brakes are the only way to go. Once I paint them, I can give them a thumbs up if they look good and hold up. If not, they will be templates to cut heavier plastic or sheet metal.
The rear tire is a heavy tire 20 x 2.125 they use here in the Philippines for mostly work, like carts and sidecars. It's the closest to a big slick I've found here. The front tire is a Michelin Diablo 20 x 1.75 I brought here from the states. Now they call it the Country J tire. Pretty good all purpose tire.