I have split backstay that goes through the bimini. There are 2 zippers that open up a slot for the backstays. A small piece of leather is sewn at the end of the slot where the bimini and backstay might come in contact. After 10 or 15 years there is little or no wear on the leather.
That's impressive! It sounds like your's is very high quality. Mine was starting to show some light wear before I installed the shroud cover
A cover that will slip on a lifeline sounds like a bad idea. In fact, I did that many, many years ago, and realized it was a bad idea. The sole exception can be where a sheet bears on the lifeline.
The lifelines are coated in vinyl so I doubt the cover is doing more damage. No idea how old they are. They're going to be replaced as soon as I can find the time. As for the shrouds, I use them in places that rub up against sheets and the bimini
Same here. Mine is slit and has zippers to close it back up. I also have padded fabric "wraps" where the shrouds pass thru the bimini
Mine has a zipper on the inside and velcro that covers the zipper on the outside. The hole has some fabric sewn into a tube and string to tie once it's installed. It does a good job of keeping the rain out
Aside from the debate if you should or shouldn't, you might try a spilt loom installation tool, it's the same idea.
When I first did this I found it to be a very difficult task. With practice it became pretty easy. The key is to bend the covers to open up the slit