Your radial arm drill press can rotate the head as well as the table. Was it necessary to do both to get the correct angle?
So, are the legs splayed in both direction OR a compound angle, right? You said that you had a lot of difficulty determining the angle, and I'm wondering how you arrived at what you ended up with. It would take some plane geometry IF they are splayed both ways or compound.
I see the following photo of your calculations ... scary!
Me, I would just hot glue a broom stick/dowel/extra leg to a plywood base, stand back and adjust it until I liked it and THEN determine the angle(s) with a Digicube. Then over to the drill press and make a test hole to see if I got my numbers right. Higher math scares me, but I like the challenge. I'm a "cut and fit" kinda guy.
This is the first time I've used such a drill press. So there might have been more efficient ways to drill these holes, but this was the best option that I managed to come up with.
I rotated only the table by 8.4 degrees, so it wasn't a compound angle(had to google it so hope I understood the term correctly). However I did rotate the table (or the piece that would contain the hole) so that the table angle direction lined up with the center line between the hole and the table edge.
I also created a test leg, but rather to test if the measured angle and set-up worked. I was happy with the result. Making the holes was the easy part. It was more challenging to use the lathe and sand the table legs into a perfectly matching table leg. It was a lot of sanding, testing, sanding, testing, sanding, testing..... to get it perfect. I did end up making 5 tables legs, as one ended up to thin and the gap between the leg and table was to evident.
I'm 34 now, and when I had geometrics in a-levels some 16 years ago i never learned how sin, cos and tan worked. I tried to but never could get the hang of it. Nice to see that my IQ (and probably motivation to learn) have improved since then.