Yes, that's exactly the "10-inch pot" that I used! I'm going to be lazy here and link back to my old post on this instrument, which has more photos and detail:
https://forum.ukuleleunderground.co...-completed-tenor-banjolele&highlight=Uke-alot
I did make my own neck. I'm not sure what guidance I can give you on the neck angle. It was designed to be roughly 3 degrees, if I recall correctly. But what I did was create a jig to help measure how far back the far end of the neck would be from a straight line, given the height of the bridge and the scale length of the instrument. Then I made a spacer of that thickness, which I put between the end of the neck and the fence of my radial arm saw when I cut the angle. That prevented me from having to try to set the saw to 87 or 93 degrees (and 3 degrees wasn't necessarily exactly the best angle anyway). In any case, the angle it was initially cut was almost right, but resulted in the action being a bit high. I modified the angle slightly with chisels, but it's actually shimmed right now to get to the correct action. One of these days, I will take it apart and modify it a bit more so that it is correct without a shim.
The neck is a mortise and tenon joint that is held on by a screw and a lag bolt, which is also the attachment for the threaded rod that spans the pot. Once the neck angle was cut, I used chisels to undercut the tenon cheeks to account for the radius of the pot. Only the outer edge of each cheek bears on the pot.
I couldn't find any plans before I made this, so I made a drawing or two for myself that were loosely based on photos of other people's projects. I will post a drawing if I can find whatever I drew up.