As is typical of queries I have posted on various topics on this forum, I am so grateful for the incredibly helpful information shared by so many. For a variety of reasons, I will go the least expensive route, limit purchases of any plastic ties I can secure, and make the rest myself. Here are a few comments on some of the posts:
1. I had previously contacted the person who had offered 3R plastic ties - long gone.
2. Do not see any means to purchase plastic ties from previous manufacturers, and limited offers available privately.
3. The ones I made previously were from 1/4" X 1/2" X 4' hardwood strips from Home Depot (see photos). I cut them to 2.5" lengths using a chop (miter) saw. Stacked several strips for each cut. Fit perfectly under existing metal ties. Tip: paint the full length before cutting, otherwise you will have small ties blown all over from the force of the spray paint. (Don't ask why I know this.)
4. The screen molding strips look great and the price is incredible, especially for 8' lengths. They appear to be 3/4" in width. Not sure I want that width or whether the strip will fit under the existing metal tie. Were not in stock in any of the Home Depot stores in my area. If I go this route, will have to order them. If necessary, may have to pare down to 1/2" widths (jig saw?).
5. I use 3 ties between existing metal ties on standard lengths of straight track.
Thanks again. Enjoy your trains,
Michael