One aspect of custom spokes (and why you send the hubs and rims to them) is they measure and create the spoke needed. No rim or hub modification is generally needed that way. Lacing and Truing does cost extra, but I’d spend it since you’ve saved enormously on the rims already.
FTFY (Fixed that for you)
...victim of Android's autocorrect I am betting on a cellphone or similar...
Yes, many stories of people who sent them measurements or provided the rim manufacturer and size info along with the current hub size off of a stock bike and ended up with custom spokes that did not fit and Buchanan's would not fix it without major issues and if they did get it fixed it was by sending the rim and hub to them and sometimes having them lace it and truing it. So, as Don R stated, if you make a mistake then it is on you and you have a set of spokes that you can use for craft projects or epoxy stirring rods or children and adult "mobiles", etc.
Motorcycle art is popular if you wish to turn old parts into lamps and many other creative reuses. Most of the time it is not rusty parts being used... They have a lacquer or polyurethane or similar sealing material that can make any old motor parts look oiled... A search for images of Motorcycle parts art or lamps or clocks, etc. will yield a huge return list.
