After two coats of solvent based color preserver the thread has a satin look. Are there any finishes that will maintain that look (as opposed to epoxy or perma gloss type finishes)? Does any one think that one brand or type of thread (regarless of price) has less tendency to fray or unwind, in other words look better when the finish has been applied (I have used Gudebrod and Fishhawk)?

You are going to have to buy a spool of as many different threads as you can
Get some scrap blank and try them See which you like

Bill - willierods.com

You don't need a blank, wooden dowels work fine and are cheaper. Not sure what you mean by fray and unwind or remain satin looking. Any finish will gloss it up although the PG is a little egg shell-ish compared to epoxy. There are additives for auto paint to dull the look but not sure that will work in rod finish.

Freddwhy (Rapt-Ryte)

You could experiment with a satin finish polyacrylic from the hardware store ... but I doubt if it will be as strong as the two part epoxy thread finishes. Many, probably most, believe the threads provide the strength and the finish just seals everything up and holds it in place. I believe it's a bit of a combination of the two. Maybe Tom will chime in with some of his knowledge he gleaned from Ralph O'Quinn who is one of the foremost experts on this topic.

Charles,
Do a bit of experimentation, but you can get a satin look by adding baby powder or talc to the finish. It will smell good as well.

You can vary the amount of talc to get the effect that you want.

Materials similar to Talc are used by varnish and similar finish manufacturers to achieve various grades of a flat finish.

Test on old blanks for the overall affect and finish you desire. Once you have the recipe, you can repeat it for your builds.

Be safe