I'll be blunt. Your 40s kit is so bad that I would be shocked if you sold more than three. Those three would be the poor souls who neglected to check for compatibility.
There are no 2u spacebars, there's an extra pipe and question mark key on the wrong rows, and you don't even have an accent escape that would be useful on a 40. R1 is for maybe three boards that people actually use. You should also include at least a 6.25u spacebar, probably a 7u one as well.
If you want to get a little more inclusive with your kitting, 2x3u would be great too.
As it is, your 40s kit supports maybe four keyboards.