Having hymn numbers on an hymn board is one of those old fashioned conveniences which may be in danger of dying out. Many places have updated to projecting the words on screens placed around the sanctuary.
Here is a PDF of numbers, 4 to an A4 sheet. You can print them on cardstock or what you will, black in the remaining background - I didn’t make the PDF background black as my printer can’t print to the edges plus I save toner this way, but I made the outlines of the numbers nice and thick so it should be easy to keep the paint off the numbers.
I’ll update with photos once we have a set made up.
My son is making a little hymnboard. You can probably get the gist of how to assemble one without detailed plans. More photos and updates to come.