Snippage

Look for a flat aluminum yardstick at Wal-Mawrt, paint stores and/or
lumberyards.
http://www.acehardware.com/sm-ace-al...i-1285788.html
Use machine screws rather than glue. They're cheaper and work better.
Try a tackle shop for stick-on rulers intended to stick on the
(in)side of a boat to check fish for legal size.
http://tinyurl.com/2q4u5c

Either of these might be available free or close to it if they bear
advertising.

I have seen a couple of the aluminum yardsticks. Most of the ones that
I have seen are wider than I have room for and I guess there are two
more things that I should have mentioned. 1)- I am looking for 48" and
2)- I haven't seen any rulers or "yardsticks" that long that are thin
enough. The fence would then ride on the ruler instead of the fence rails.

Now the tackle shop stick on rulers. Hmmmm. I just don't know about
trying to find an accurate ruler in a fishing supply store. :-) HONEST
OFFICER, MY RULER SAYS IT IS OVER LEGAL SIZE!! Seriously though. I
wonder how accurate they would be.

Thanks anyway.

Wayne