My sunvisors are going back on the car in a few minutes. I finally completed my rebuild and I am reasonably satisfied. I used the same material I got from World Ulph. for my headliner. It is a bit tedious to work with but after it sits for a while it stretches and smooths out nicely.
The subject of my initial post was asking for advice on filler / padding paterial. After seeing what 37 year old foam looks like I was not interested in repeating BMW's original selection. What I wound up using was more than perfect. I was able to cut the patten with scissors and then use a razor to cut a simple internal fitting for the visor center frame rod. I opened up the edges and pulled the frame in; I closed the edges and center area using weatherstrip adhesive. This process completely surrounded the frame with material.
When sewing the material I simply traced the old visor (cut off around melted seam with a razor) and sewed along the line then trimmed up. I also made a simple mirror pocket since the old holder was formed plastic and not reusable. I simply traced the hole and carefully sewed on an underlay (face to face then turned inside out) when I then top stitched very carefull. I left the entire side open with about 0.5" of material and hand sewed it after inserting the padded frame.
The padding I used I found at JoAnn Carfts; it is "Soft-n-Crafty" Premium Densified Batting; also called Nu-Foam. It comes in many sizes. I chose 15' c 17" x 1"; a single piese was enough for both visors.
In the photo my visor look a bit puckered. This will eventualy work out as they warm and stretch. In the photo I included the bad, the extra material, and the old dirty visor skin for reference.