I'm ready to take the plunge and get my second suppressor.  My first is a Sceptre II which I am pleased with.  I'm ready to purchase a centerfire pistol can and need some help.  I have a Scorpion Evo (with 1/2x28 threads) and a CZ SP01 suppressor ready (1/2x28 threaded barrel, suppressor height sights) on order. I have other 9mm pistols that could potentially be converted for use with a suppressor (Glocks, Sig 226) as well as a 1911 although I don't really see me doing that due to the cost.

I understand that I need a piston for the SP01 to allow the barrel to move during unlocking.  I also understand that I don't need that for the Evo since it has a blowback action but can I use a piston on the Evo?  Or will I need a separate fixed mount for the Evo?

Any recommendations on which suppressors I should consider?  I will be using this strictly for fun at the range not for home defense or TEOTWAWKI.  Price range would be mid-tier; I don't mind spending more for features that make for a better experience but I don't need the one made of unobtanium and used by the SEALs. Weight, within reason, isn't a big factor and quieter is better than louder. I'm not sure about whether to get a 9mm can or a 45ACP can although I don't really see myself using it on a 45.

Lastly, what vendors should I check?  I'm aware of Lanbo's, Silencer Shop and usually google or check slickguns when I make this kind of purchase.

Thanks,

I have an AAC TiRant 45 can with Pistons for my Sig P220, Glock 19, and 9mm AR. Gets more use than any other can I own.

Love my tirant 9mm

Check the Rugged and Dead Air pistol cans.  Both are 45ACP and can be used compact size or full size.  That gives you the option of more suppression when length doesn't matter and a compact solution when it does.  Both are user serviceable.  You would be good with everything from 9mm/45ACP to subsonic 300BO.

^ That.

If you can't find any in stock or don't like the prices you're seeing, you can try the SilencerCo Octane or Griffin Revolution cans as well.

IMO, for your first pistol can, go for maximum suppression. If it's just for fun at the range, then it sounds like length/weight won't be much of a factor, so I'd avoid the short "K" cans as they don't suppress well at all. Modular cans are great (able to take out a space to make them shorter), but you pay for for that feature. 45 cans are versatile if you ever think you'll shoot 45, but they won't suppress 9 quite as well as a purpose built 9mm can, and they're generally bigger/longer than 9mm cans too.
You'll need a booster for pistols (most any 9mm cans will come with one). You will need a fixed barrel mount for the Scorpion (or any 9mm rifle/carbine) - using the piston is not recommended.

Tirant 9 is probably the best suppression available for 9mm still. SiCo Octane 9 is a good choice too. Griffin Revolution/Resistance 9mm, Rugged Obsidian are also good choices.

After a little more research, I'm starting to get some ideas.  I wasn't really considering a 45 can but having the option of multi calibers sounds pretty good although there is a weight penalty.

The Griffin Revolution 45 sounds promising.  The modularity sounds like it might come in handy, the stainless baffles and user serviceability are important, and having the option of a 1/2 x 28 piston included in the purchase price reduces the initial cost compared to other 45 cans that come with 45 pistons.

One thing i noticed on Griffin's website is they offer fixed mounts for $85 but they also offer fixed barrel spacers for $30.  It sounds like I could use the fixed barrel spacer to convert a 1/2 by 28 piston to a fixed mount for a lot less than a fix mount for use on the Evo.  Is that what these are for? https://www.griffinarmament.com/Revolution-Fixed-Barrel-Spacer-p/gafs.htm  and  https://www.griffinarmament.com/Revolution-Fixed-Mount-p/rfm.htm

I would go with an Obsidian. It accepts SICO Octane mounts and pistons. SICO sells a fixed adapter for the gen 1 scorpion. (I have both a revolution and obsidian in jail)

Are mounts an issue?  I have a gen 2 Scorpion with the 1/2 x 28 threads so I don't need anything special.  Silencer Shop sells the Griffin Revolution with your choice of pistons so I can get a 1/2 x 28 for $642 but the Obsidian comes with the .578x28 for $654 and the 9mm piston is $75 extra. That's a price difference of (wait for it!) $87.  Yes, I would have a piston for 45ACP but I may never need it and can always purchase it later if needed. The Revolution is in stock at the moment at Silencer Shop.

Otherwise, the Obsidian and Revolution seem to be very similar in weight, construction, sound reduction, versatility, serviceability and price.  Is there anything else that I should consider?

I think both those cans are good choices.  Rev is proven and rugged is the unproven but has features ppl like, in your shoes I'd likely choose rev