I wish that 90% of my 25s had been based on the last few years of the Canadian Penny with a copper cladding over a ferromagnetic center. Those would have worked with magnetic sheet for transport.

My 6s are mostly mounted in fireteams between 2 (sniper team, comms team, LMG or light AT team), 3 (tripod support, heavier AT or mortars), to 3-6 in for standard grunts (A 4 and a 6 makeup an articulated 10 man squad).

One of the big things I used to show the higher quality troop types in GZG rules was to allow more articulation than you'd get in poorer troops (better ability to coordinate, split fires, do complex squad tactics, etc). The barely trained green troops from the backwater planet might well have no articulation (whole squad as one entity), most trained regulars might have a rifle element and a support element in a squad or two equal sized chunks with light support in each, and SF could have a 12 man team broken into as many as 4 different elements (3 being more common). In addition to using larger quality dice (a big factor in many parts of resolution), the greater articulation meant more actions, more complex tactics, and that a smaller group could be matched against a bigger force that wasn't articulated or very good and the match could be quite a fun one (SF team escaping while being pursued by 4 squads of mixed regs and militia that had little articulation as one example).

The magnet per-figure idea is interesting. Maybe something I'd look at later. To make my bases interchangeable, I put a brass pin into each figure's base and drilled a hole in each base's figure socket so I could swap them in and out, but that can be fiddly and magnets could fix that.