Which Piston Rings?

That will depend on the pistons, compression and the finish you end up with on the cylinders. Same for the bearings- depends on the crank, hp and application. You want the crank and rod bearings to match the crank as it relates to how it is machined. There are different thickness and materials of bearings,

I would recommend that you speak with the machine shop. You cannot simply throw a bunch or parts together. I would avoid any Ebay or low buck "kit" that are just that- cheap chinese crap someone threw in a box and no tolerances or quality control done.

If you do not know of any competent engine builders find one- I would start with Woody at Fordstrokers, Mark Oneal @ CHP, or Rick on this site.

when talking about brands, i prefer sealed power and perfect circle rings. i also like moly faced rings as well. you might look into what is known as a zero gap second ring to pump up your compression pressure slightly. as for size, that will depend on the size of your cylinders, among other things.

Sealed power has some rebuild kits on summit racing. I'll be getting a kit for about $330 once my block goes to the machine shop and lets me know what sizes I need.