Junkyard 5.9L Magnum + Edelbrock LA heads build

At your build price level, I would go with any quality ring: Hastings, Sealed Power, Mahle. I just looked on RockAuto and saw both Moly top rings, and interestingly, an Enginetech set that says it has a ductile iron top ring.... ductile iron is supposedly good for higher heat use. (I just hope that description is accurate, as the price is low! When I have question on a part from a site like RockAuto, I take the PN to the MFR's website and research it.)

I have used standard replacement Hastings and Sealed Power moly top ring sets in my 2.6L Mitsubishi turbo rally car engine, running 8.2 true SCR and 14-15 boost, and they worked fine. But, I always re-bored and had a good hone job on them.....

This may not be wlecomed input....Your results will have more to do with the bore conditions than the ring itself. If you really want to guarantee longevity, then a re-bore is almost a given. You can borrow a good bore gauge and run it up and down for taper, and then vertical and sideways for out-of-roundness, and see what you have. It's clear from your 2nd pic that you do have some level of bore wear; the cross-hatching is all gone on a couple of places so I'd expect some of both taper and out-of-roundness. The former can kill rings pretty fast, and the latter hurts the seal. IMHO, a good, straight bore is the foundation of a good engine.