I thought I would attach more pics of the pipe locations outside and inside the house. After looking at it more, I guess I could easily drop the pipe a few inches below the joist (and box it in) and come in through the exterior stud bay and closet wall 2x4. I wish I did not cut holes there already!! Although I still think I will have just enough clearance for slope if I stay with original pipe punch through.Wayne ... first thanks for taking the time for such a detailed reply.
Yes, u-turn is not ideal, but I was hoping to stay in the one joist bay and save boring 2 holes in the joist to the right of the tub drain just to pick up the vertical vent in the stub wall, and losing the 1 1/2 inches in height for the joist flange. I attached a drawing scenario 6 to show what I was thinking.
I can still go with drawing 5 and go over one bay to avoid the 180 degree u-turn, I think I have just enough height, but because I will lose about 2 inches to avoid cutting the joist flange, it will be close.
I do have a 16 inch joist bay, however, where I would like to enter the main house is through the rim board just above the top plate on the house/garage wall (lower left corner of drawings), which is about 4 1/2 inches from the bottom of the flange (or 6 inches down from subfloor). See attached pictureView attachment 82940. This is in a closet back wall in the main house, so I do have the option to drop it down lower into the garage space and go in through a stud, lower, however, this is just to the right of the main house/garage entry door, so it would look a little ugly, but I guess I could frame in a chase around it for aesthetics. I would prefer to stay in the ceiling/floor cavity of the garage if possible.
The tub is freestanding/claw feet, Bain Ultra 6636, and has the overflow and drain above the subfloor, so only the drain pipe coming through the bottom of the subfloor. Shower will be a 60 x 36 pan with a corner glass walls, so no alcove wall to work with unfortunately. The room View attachment 82939right wall is directly over a joist, but if I have to jump a joist bay, I have the 45 degree stub wall I can get a vertical vent in and eventually up the right wall above the bottom plate.
I think I answered your feedback questions, but if not let me know. I may do some more calculations, but if I stay close to the flange on the right joist (which Boise says you can actually cut the i-beam web right to the flange, as long as the flange is intact), I should be able to make the slope work with drawing 5.