Spectra for lanyards? Epee deadeyes?

[osteoderm]

I've used 3-strand dacron for lanyards. Taking them up is a bit of a bear with all the initial stretch, but once set up, they work well enough. The three-strand looks right too. The geometry and loads of a traditional rig for which deadeyes & lanyards are properly suited generally allow or even call for a certain amount of flexibility in rigging materials.
Near deck level is where you'll appreciate the preservative effects of a tarry rig most. Many coats of the right mix will dry and harden to a smooth black surface, almost shiny at first, and pose no particular danger to your uniforms. Properly well-tarred 3-strand line, with the conts nearely filled full-up with the stuff, look just great to my eye. The tar also shields the line from UV.
As for which "right mix" to use, well... that's a real matter of debate! Every traditional boat I've worked on has their own "secret recipe", more-or-less suited to their usage and location, ie., something that works great in temperate climes may well run right out of the rigging in the tropics.