I want to put together a Scratchbuiding Starter Kit of sorts for myself, basically consisting of various sheets of different thickness styrene, maybe a textured piece, and some different gauge styrene rods for fuel lines, electrical, etc etc.
My Osprey Masterclass: Armour Modelling book has a section on a build where someone uses 20-thou rod for certain details so that's one thing to get this "kit" list started.
My question is what are the usual thicknesses of styrene used? And what gauge rods are usually used? I do have some copper wire, and metal gardening wire but would like to expand my scratchbuilding skills.
The first use for this "building kit" will be to make an M51 quad .50 trailer:

I have a leftover quad mounted .50 from an M16 Gun Motor Carriage project that was abandoned and I'd like to scratch the trailer. Either the dual-axle trailer or the single, not sure yet. I have read some great tutorials in the Masterclass book on making weld beads and numerous other things that I'd like to put into practice!
Thanks for all your help expanding my skills!
It is GREATLY appreciated!