In terms of the physical models, it also juut depends on how flexable your play group is. For example, I sometimes build gangers with more weapons than they're equipped with but leave them painted black and then paint them in when I acquire that weapon. Some groups are fine with pistols and CC weapons not being represented on your character etc. Other groups are also fine with using other kits such as the Stargrave one, or 3D printed parts.
When I look at the grav cutters in particular I really don't see why you couldn't just kitbash boards and shields. But again, it'll depend on who you're playing with.
I just mention these options because I think it's a bit of a shame when a player's imagination has to be limited by the cost of GW plastic (and as someone who finds magnetisation tedious).