Very nice work!
Here's how I designed my full size model, stackable, interlocking field/transport racks.
Each is 4 feet long so it can be carried in one hand "loaded" with models in either the horizontal or near vertical levels. Holes in the swivel out legs allow for standard 1/4" round tent stakes to prevent even high wind turnovers, and up to 4 racks will slide together, interrlocking into sort of a square where that same 4 stakes hold the 32 model group.
Each is constructed from a single 1" x 3" by 8'-0" yellow poplar board, 1 - 1/2" dia x 36" hardwood dowel, 2 - 10/24" x 2" round head machine screws with wing nuts, 11 - #8 x 1-1/4" flat head wood screws, some yellow carpenters glue and clear polyurethane finish. I made 10 of these racks which have served me very well for a long time, several have been given away to fellow rocket flyers over the years. I still have the five a regularly use. If memory serves me I think I spent about $60.00 for the lot but that was over 15 years ago
I made up enough 18mm and 24mm burnt motor casings (sanding down the nozzle end to slip into the motor mount without stretching out the motor tubes) to sleeve over the 1/2" dowels to handle 13, 18 and 24mm motor mount models.
The design allows the fully load racks to be carried to and slide into my Van for transport, Taking up an 18" x 63" area of van floor space..PLus hangover fins of course
leaving plenty of room for launcher equipment, batteries and such. These racks makes it quick and easy loading and unloading on the field and at the house. When not in use the racks stack together alomst flat on a shelf out of the way.
Hope this helps