Hey Jimmie,
I always use a coping sled to do any rails and first I set my bit run a test piece then I make
a back up stick to sit behind the rail your clamping down and to the back rest of the sled.
Not sure where your check book is but I would highly recommend you check out WoodHavens sleds.
they are super simple and dead on accurate. I also cut my rails about a 1/32 to 1/16 over length so you know you are actually getting the full tongue for the rail end. Once I have my ends profiled I then run my lineal for the rail and stile.
Set up on the rail as there you can line up the tongue with the groove cutting part of your Stile Bit.
I always also save a sample of both the rail and stile separate from each other for the next run. Label
it and put a big X on the end you use for future set up and reference.
Hope this answers your questions, if not please inquire again.
Kind regards,
Tim J Ziegler
Ziegler WoodWork & Specialty
I always use a coping sled to do any rails and first I set my bit run a test piece then I make
a back up stick to sit behind the rail your clamping down and to the back rest of the sled.
Not sure where your check book is but I would highly recommend you check out WoodHavens sleds.

Set up on the rail as there you can line up the tongue with the groove cutting part of your Stile Bit.
I always also save a sample of both the rail and stile separate from each other for the next run. Label
it and put a big X on the end you use for future set up and reference.
Hope this answers your questions, if not please inquire again.
Kind regards,
Tim J Ziegler
Ziegler WoodWork & Specialty