"Paul Tomblin" wrote

According to NOTAM, it was "GAC" in 2003, the
last time I came, and it's "GAC" now, so did that change in the interim
and change back, or was that a mistake by the RST signs?

Dunno. GAC is good, because less letters mean bigger letters, means readable
from further back. The best is big BOLD letters. A fat tip black marker
and a full piece of paper, or light posterboard will be fine.
--
Jim in NC