Yes, it seems like your tring to put a square peg into a round hole.
If you see it, you understand it.
I can't believe I hadn't thought of it long before.
It's not as complicated as it seems, (I hope the pics help).
I have a small snap at the waist that goes all the way around you.
The rest of your back is open, but your pack fills in that area.
I have the insulated bottoms on over the wind pant, but that's it.
As long as your feet and the rest of your body are warm, what little section of your legs is left doesn't get very cold.
The L/R pants were a lot easier to make than the jacket.
Sewing the first stitching row of the 2 pieces together is the only tough part because you want to catch just the very edge of the insulation so that you don't have a huge round seam. If you do have the round seam, sewing them together is the real pain.
All in all, it's just like sewing a standard pant, (very easy).