The TZ is sort of a combination of the good features of the SIG P2XX series (most of its internals) blended with the good features of the Walther P88 (ambi controls). The mag release is like the P88 in that it can be operated from either side without modification. To do this, the magazine catch notch is centrally located in front of the mag towards the top. Regular one sided mag release guns like the P2XXs, the mag catch notch is on one or both front corners of the mag.
The mag to my TZ is identical in exterior dimensions as my P226 mag. The mag of each gun will go into the frame of the other. Due to the different locations of the mag catch notches, they, of course, do not lock into place when the mags are swapped. If held in place, the P226 mag would seem to work OK as the mag does not provide any obstructions to the bolt. I am not going to actually try to shoot a P226 mag in the TZ with my weal hand holding it in place. On the other side, the TZ mag will fit flush with the frame of the P226 if held in place. However, the ledge on the follower is too low to activate the slide stop of the SIG even though the mag is flush with the bottom of the frame. You can probably replace the follower with a higher ledge and make that part function.
To make the TZ mag to function correctly in the SIG, a mag catch notch will have to be ground into the corner of the mag. (Along with the follower replacement.) To make the P226 mag work in the TZ, a notch will have to ground into the front of the mag. Since you have P228 mags, these will be too short for the TZ if you wanted to convert.