It seems necessary to "waste" as much as 60 feet of rope in either
side. If I support the center insulator, then double that.

Is there a better way?

I'm not sure what the problem is, yes, it takes a bunch of rope if
you can't climb the tree.

I usually don't bother with pulleys as I prefer to get the antenna
up as high as possible. You will lose 15-20 feet of height (or more)
using a pulley compared to not.

Tor
N4OGW