Since the MA02 is the only SF lamp assembly of its design, neither spares carrier holds it perfectly.
IMO, the SC3 holds it much better than the SC2. In the SC2, you are tempted to use a small piece of tissue paper or bubble wrap to limit the movement and rattle.
The SC3 carries only 4 extra cells as opposed to 6 in the SC2. You might base your choice on any other SF lights you own or plan to buy.
Mark