I used two 28" rims with 28 holes as a basis. So they have a spoke hole per inch. I used them to create a 36" rim which also has a spoke hole per inch, so the 36" rim has 36 holes. I ride such a rim on my main 36" uni since feb. 2018, so it is somewhat rigid. Here I showed creating the rim without showing special tools, so everyone can do it (although I used a mill):