Goats and Bits

[Nanno]

Harnesses made for miniature horses are usually a good fit for full-sized wethers. If there's a choice between Mini A and Mini B size, choose Mini A. Mini A horses are a lot smaller than goats height-wise, but equines are overall much stouter than goats so the Mini A harness generally works a bit better.

I don't usually recommend making your own harness unless you have a heavy duty sewing machine and a good working knowledge of how harnesses function. Some experience harnessing and driving horses is recommended before attempting to build your own goat harness. All the principles of harnessing and driving horses apply to goats as well. If you have a chance to take a horse driving class, take it! It will help you with your goats.

I've written a few articles about harnessing and training goats to drive. The driving articles start at the top:
https://www.goatorama.com/articles/

Good luck! Let us know how you progress!