Endura12 may not be the best choice for standing rigging. E12 is Dyneema/Spectra which exhibits creep (sort of a molecular stretch). You could potentially use 12-strand made from creep-free fibers.
As far as hardware, check out some of the offerings for Precourt Systems (
www.precourt.ca), you might be able to figure something out.
For thimbles, take a look at solid cast thimbles, they are very tough with no rough edges to chafe.
Bob