Steve it really is not hard to do but you need repeatability. Now I will see if I can find the article or thread he talked about this but here is a link to his album and he shows his jig there. Mike was one of the first people here that helped me get the Segmenting forum up and running because he showed the same interest I had. He even started the thread and again I say this, that it should be stickied or pasted as a subforum, No comments just photos of segmented pens. You can look for that one in the segmenting forum
I even thought that was his photos you shown as an example and sure enough they are in his album.
https://www.penturners.org/media/users/mikespenturningz.15324/page-2
I agree look at utube for bandsaw sleds and adapt something that will work for you. Just need to be able to hold the blank on the angle you want and then a stop block. to control depth of cut but the bandsaw is the easiest way to cut those. So many sled ideas out there.