I've created a variant with filename ending _nuts if you'd like to try it. I'd suggest making a single print first to see whether it'll actually be rigid enough for your purposes. Introducing a nut channel in the part leaves some unusual interior spaces so I'm not certain that it would print perfectly. I've also removed the hole through from the nut space to the top of the part which might mean you need to change the screw length. If you have any other suggestions feel free to write back.