Compound drill shop project

Compound drill shop project
with this video I show how to do the calculations for a compound angle for drilling
using dimensions distance from top hole and bottom hole and height of block
Video link
https://youtu.be/vswa3OhaUA8

I need to do some compound milling and drilling,Ill give this a good going over when Im ready to do it I just hope I can comprehend it....my brain aint all it used to be and memory is almost gone. I hope to get started on it by next summer...I hope. changeing angles of valve guides & seats in some of my new cylinder heads along with totaly reworking the valvetrain system with totaly massivly different parts. ( aircooled vw stuff getting nascar upgrades) years ago it would of been eazy, nowdays...not so much ,it's a good thing I have 5 new castings to work with.one to get it all right&figured. still have lots of welding to get done on them first. thanks for the post!!! I hope I can figure it all out.

Thank you for your comments
Ray

Ray, does your shop have a compound sine plate? I picked one up a few years ago, it seems it would be used differently, then your example here where the 2nd axis is rotated but at the angle of the base sine plate. Am I wrong in this thinking?