Max,
I'm also talking about building a model wheel that represents a real historic wheel, whether it be a US 57-inch artillery carriage wheel or a British 12 spoke wheel from 1780; what I'm saying (just like Douglas) is that for the purpose of taking the scale model to the range and firing from the bench or the ground, that I don't think it's necessary to try and fashion the wheels with the same degree of tightness in the mortice and tenon joins of spoke to nave, and spoke tongue through felly joins that a larger wheel carrying more weight, and having to endure greater shocks needs.
For example: I've got that CVA .69 cal Napoleon that I used for the postal shoot, and even after 25 years (or so) the wheels are still fairly solid. Now it would take a great stretch of the imagination to think of these wheels as actually being constructed like actual dished wooden compression wheels even though they pretty much look like the real deal (unfortunately 12 spokes instead of 14). There is a steel tyre, but the only thing holding them in place are screws, and you can see gaps between tyres and felly. All the joints of the spokes to nave and felloes are fastened by glue (not by friction and compression), and the four hub rings are held in place with nails (gaps). Now Max, if these wheels were somehow enlarged to 57-inch diam. and put on a real CW carriage carrying a Napoleon, and then we started to pull the piece down the road, we'd probably make it about 12 inches before the whole thing collapsed into the dirt. Now do you see what I'm trying to get at?