I'll be spraying my 70 within the next week hopefully if its ready. It will be red with black stripes RM Urethane BC/CC. The kit ive got is from OPG. Ive spent several hours doing the search deal and answered most questions (first time using a stencil kit), I've seen some that spray the stripe color first, then the body color and vice versa. Some that spray clear, stripes then reclear and some that chance lifting the base color with tape. I was planing on spraying the car center black first, apply stencils and then body color. Now from searches ive decided against that and to spray the body color first.
What i haven't found is ideas/tips to align/measure the stencil. The instrucstions are in decimal figures. And the OPG instructions says to stop the deck stipe 2.0 short of the molding, which i know for a fact is wrong.It goes all the way to the window.
Is it correct to let the overspray between the rear deck lid and body?

I don't know about correct but I would tape it off for a neat straight line viewed only when the trunk is open.

No doubt look better taped off and lines straight, but from a search post, doubted the factory would have done the same and the overspray allowed into the trunk jamb. Guess my question would be if the origionals were taped or not.

Not sure what the factory did, but the first time I did it, I let the overspray go into the trunk area and it looked like sh**. Definitely recommend taping all the way.

I think I'll use your advice and tape it off. Has to look like A** with the overspray. Any advice on laying out the stencils?

Just sent you an email with pix that might also have some value.