Andy,
Are you still using the 4 x 6 blocks with the colored top and the NCC logo laser etched into the side? Those things looked sweet but were a pain in the rear every year when we had to sand them down and refinish them. I used to have to get the wood through my wife's dad because it couldn't be pressure treated to be laser etched. Then spend days on end cutting the mitred ends, painting, sealing and putting the nail in the bottom. Looked sweet but we never got more than two years out of them.
I don't really have any ideas for ya, just wanted to say those old tee markers were a misery.
Also, check out this link:
http://www.turfnet.com/randy/the-best-tee-markers/