Of the bunch, I guess you can say I went the most nuts with mine.
In 2004 I found a German blued steel 6" longslide with Bo Mar sights and decided I 'needed' it for my 3rd gen G21. So, with a Jarvis 6" barrel and a set of internal slide parts from Lone Wolf, I made myself a G21 Longslide.
The Jarvis barrel gave superior case support and the 4¾ oz more mass at the muzzle from the longer slide and barrel, coupled with the 28% longer sight radius and great Bo Mar rear sight, gave me a much better aiming pistol. All that together made for an excellent platform that is easy shooting and accurate as heck.
Not content with stopping there, later that year I also asked Kevin at KKM to develop a 45-10MM conversion barrel so I could also shoot 10mm from it with just a barrel and mag swap. Turning it into the world's first G20/21L.
During the development, I found that one only needed the newest .45 Loaded Chamber Indicator (LCI) version extractor to use with the slide as it's 'claw' is canted at an angle giving it a better grip on the smaller dia 10mm case while the original flat extractor (shown in the picture of the pistol above) is vertical and doesn't grip the 10mm case as well.
Over the years I hardchromed the slide, did some custom trigger work, added a FO front sight, and added a magwell for some competitions I used it in. I also bought a 24 lb recoil spring assy so I could swap it out with the 20 lb standard one I used when I wanted to shoot hot 10mm or my newest handload, .45 Super.
I only shoot the lighter weight .45 Super loads through it; 230grn at 1,260fps and 200grn at 1,307fps as you need a comp on your pistol to shoot the heavy weight bullets at high speed so you don't tear it up and I don't want a comp on it.
My G21L will feed anything including some of my old Speer 'Flying Ashtray' handloads shown above with their early HP with a huge hollow that are notoriously hard to chamber in many 45s. BTW, you can see the newer LCI extractor in the picture above clearly showing that the chamber is empty.
So, be it 45acp, 45acp+p or 45 Super, my G21L is ready and waiting to have a go with all of them and with a simple barrel swap and 10mm mags, it becomes my G20L able to shoot all of my 10mm loads including my 'nuclear' 165grn handload producing 1,589fps!!!!!