Bern,
I agree, if sailing cat rigged there is no need to use the compression strut and saddle.

When running a jib the compression strut is needed.
The jib comes down past the primary load bearing bridle wires to the pole and if you don't use a compression strut you can't get enough luff tension on the jib. I have tried it without the compression strut and found it really is needed when running the jib.

What is a bottle screw adjuster?

Regards,
Phill

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!