If you're talking about a LP build....straight tenon, angled neck pocket. I use an MDF template with angled wedges under it, secured to the body with masking tape and CA glue. Then route the pocket with a hand router and template bit. For cutting the neck plane into the guitar top, I use a hinged router planing sled propped up to the correct angle. For both tasks, I use a cheap level finding app on my phone to confirm the angle.
I've never decided that I will absolutely do only angled neck pockets or build the angle into the neck heel. I've done it both ways, both get the job done. It's just a matter of choice.
Either way, it's done on my knee mill. I calculate the angle I desire and then cut the mortise and neck heel leaving me some room for adjustment. WIth the neck clamped in place I measure the neck plane extended over the bridge location for bridge height, and make adjustments until I'm in the right range.
It depends on the build. For most flat-top set-neck guitars, I angle the tenon. The way the factory did. I use a protractor to get the angle I need, draw it out, cut it. And I use the tenon box jig and a router for shoulders when applicable.
Sometimes on some difficult builds, I'll angle the neck pocket.
Sometimes I'm called on to do a rare or odd build. In those cases, I mock up a tenon and a neck pocket out of construction lumber and get it all sorted, then transfer that procedure to the real thing. I've had to learn that the hard way a time or to.
Sometimes the plans are wrong. Even though they look "all pro", they are sometimes not. I have found that when I do a job based on paper plans, its' best to mock everything up. Then when I have the mock tenon in the mock mortise and body, I lay out the string line to ensure that it is neither too high or two low.