*cracks knuckles*
Alright. Safariland marketing and organization sucks. The holster finder doesn't work. Everyone hates it, even us who work with Safariland. That being said, ignore the numbers of the GLS platform. The X denomination is simply for the *mount* that comes with the GLS and doesn't refer to the weapons it fits. You can find GLSs in black, FDE, OD, and WG, left or right handed, in six variations not including the mounting systems. And really these six variations are just two - the GLS and the GLS WF (Wide Frame). The four variations of GLS and two WFs are just different lengths. All pistols that fit one size of GLS or one size of WF will fit the others, but you may have exposed muzzle or extra space in front of the muzzle depending. Now - as to fit. No GLS will fit a torch nor a suppressor wider than the slide of your pistol, while all will fit suppressor-height irons and dots, as long as they aren't too funky. Between the GLS and WF you can fit *every* pistol with a standard frame layout, so no Lugers or things like that. Tiny guns like a PPK or Glock 43 wont fit; nor will massive guns like mk23s or Deagles. Beyond that one of the two will fit pretty much anything you can get your hands on.
So when it comes to selecting a GLS there's a few things to look at. First, what guns do you want to fit? G17s, non-railed 226s, M&Ps, and *most* 1911s will fit in the GLS, while railed 226s, FNs, Sig 320s, Berettas, etc. will fit in the WF version. Next, pick a length. If the longest gun your gonna put in is a standard 4.25" G17, M&P9, or 226 then you should get a "Standard Length" model. If you have a 5" Government-model 1911 then you'll want the "Long Length". Glock 19 your longest? The the "Compact Length" is the one for you. Got something really tiny like a G26? Then the "Sub-Compact Length" is the go-to. The WF models just have a Long and Standard. Based on your list above you need up to two GLSs; a GLS Standard Length (or Long Length if your 1911 is a 5") for most of the pistols listed and a GLS Wide Frame Long Length for the M9. Color is up to you but black is by far the most common, with FDE being a close second. WG and OD are hard to find though if you were in the US I could offer you both as we have a small stock. Who knows there may be some floating around the UK. All GLSs are Injection Molded and easy to paint if you so choose, so doing your own work is always an option. The final thing you have to choose is the mount. Now, let me preface this by saying that all GLSs (and the majority of all Safariland holsters) follow the same three-hole pattern, which means every holster (with a few small exceptions) will fit all Safariland mounting systems - a system that is quickly becoming universal. So if you don't like a mount you can switch. My personal favorite mount for all my Safarilands (and I have like 30 different setups for different things) is the AUBL, which is a UBL (Universal Belt Mount) with both vertical adjustment options and canting abilities and the VUBL which just has vertical options. In the UK I ran up to two leg drop kits. Then there are three heights of non-adjustable UBL (though most mounts still have at least 15% of cant allowance built-in), two or three different hip-height belt mounts, paddle mounts, MLS (Molle Locking System) mounts for vests, webbing chest mounts (at least, coming soon if they aren't already out), and probably a few more Im missing. That's really up to you on what you want. I've used all of them for one purpose or another over the years. Without knowing which mount you want I cant say exactly what your three numbers are beyond 57X unfortunately.
Now, an add-on. There are actually a few more GLSs that are far less common, and not applicable to your needs at this time. There's a small gun GLS for things like P365s and G43s (though the new Shenandoah holster is far better IMO), there's an IWB (Inside WaistBand) GLS for concealed carry, and I think there's an under the arm version too for small guns. Figured Id mention them in case this becomes the go-to thread for GLS info in the future.