Which kits are they? The Bofors is most likely the old Airfix kit, no experience with it myself. The Stuart is the Matchbox kit or one of the Revell reboxes, unless it is 1/72 then it is the Hasegawa kit. Great little kit there.
I always have a couple of Braille scale kits in my model tool box for just such occasions. Of course, you can always put small 1/35 scale kits in the box like the Kettenkraftrad, M274 Mule, or one of the mulitude of 1/35 scale motorcycle kits.