As you've heard before, the best choke for your 500 will depend on your expectations and ammo selection among other things. You can hit the lotto and get the right one for you as I'll explain in a second, or you can spend a fortune in time and money trying to find the right combo. Again, it depends on what you're after.
Around 20 years ago, I was able to get a Patternmaster from Mike as I was going thru Eastern Kansas. I've yet to find a better choke tube for an 870/1100 on ducks/geese from 25 and out. As I told Mike years ago, "I simply put it on the beak and squeeze, at any (reasonable) range.". In my particular case, I was shooting handloads around 1550 fps and the PM held #2 & #3 steel around 75% @ 45 yards, in 30" circle (my standard). At the time, we were having to deal with crappy OEM steel offerings (and they'll admit that in private) and we were all looking for something to kill waterfowl as good as the lead we'd had only a few years prior.
A few years later, I ended up with a new SBE and after trying the Standard issue 5 chokes, I went back to PM. The results were not to standard with either OEM or hand rolled as they were with the Remington, so I moved-on to Briley and Carlson. I had improved results with both the Briley and Carlson in LM. I was able to tweak a couple of handloads to get me within standard but it wasn't the stone-dead killer to which I was accustomed until I had it back-bored and secondly (years later) tried a Foiles Strait Heat.
I've used the Strait Heat the past few years Turkey Hunting with excellent results and it's probably gonna be in this shotgun for the foreseeable future.
This past season, I carried a A400 Extreme everyday and put the SBE in the pinch-hit roll. Again, I tried a few different chokes including the brands listed above and the Roberts Triple Threat T1, 2, and 3. I had excellent results with the T1 on decoying ducks using both Black Cloud and Blindside 3-inch #3's and a Strait Heat for all other applications using mainly a hand load #2 & BB at 1500 fps. I'm going to extend and polish the forcing cone on the Beretta and see what this does to the patterns but for now, I'm really liking the SH.
Good luck in finding the 'just right' recipe. It gets annoying as hell at times to find it but in the end, it's worth it.
Pain or damage don't end the world. Or despair or f-ing beatings. The world ends when you're dead. Until then, you got more punishment in store. Stand it like a man... and give some back.- Al Swearengen