RE: CZ magazines...
I've had a BUNCH of CZ-75s and CZ-75Bs over the years, and know a bit about the magazines used in those guns -- but know very little about the newer hi-caps used with the SP-01 guns.
CZ originally made their own magazines, and at times have farmed out production to other companies. I know, for example, that Pro-Mag made some of their factory mags for a while, and had a number of them. They were indistinguishable from other CZ "factory" mags and performed beautifully. (They came in packages that identified them as CZ factory mags, but on the reverse side of that same page you could see a small Pro-Mag stamp.) I've NEVER had a problem with CZ-made or CZ-outsourced mags.
For the past 6-8 (maybe longer) CZ has had Mec-Gar make MOST of their factory mags. Mec-Gar also makes their own version, under their brand name. The mags are NOT identical -- the CZ and Mec-Gar branded mags often had slightly different followers.
During the years when CZ was making their own or using someone other than Mec-Gar, Mec-Gar's versions worked well in the standard CZ-75B model, but would NOT work in the CZ-75 (called "pre-B"). Mags made for Tanfoglio guns often worked in the pre-Bs, however. The difference was that the top of mag channel was narrower in the pre-B models, and the Mec-Gar mags woud not insert fully, or if inserted, would not drop free. (We've since learned how to open up that area with a flat file...)
Mags for the 75s (pre-Bs) can be purchased from CZ-USA. You can use Mec-Gars for most other models.
Mags for the compact CZ models are harder to find, and when bought from CZ, more costly. Pro-Mag magazines for the compact models, unlike other Pro-Mags made for the full-size guns, work well. Back during the ban, a bunch of us used the CZ-75B compact mags, in .40, as hi-cap mags for the 9mm compacts. They worked beautifully, without the usual Pro-Mag issues.
Note: "compact" mags made for Tanfoglio guns won't work in CZ; the Tanfoglio mags are shorter, and won't lock into place. Mags made for small-frame Tanfoglio guns work beautifully in CZs, and vice versa.
Unless there's been a change, the full-size models, ranging from the 10-round mags, to the 16-round mags, all use the same springs. (That may be the case with the 18 or 19 round mags, too -- I just don't know.) I would NOT expect the very-high cap mag springs to last as long as the others, especially if left loaded for long periods.
