Not that it applies to anybody in this thread (except maybe Jack), but if you plan to race Hobies, electrical conducting tiller extensions are prohibited. No aluminum or carbon fiber allowed.

Quote
11. TILLER ASSEMBLIES
11.1 The tiller extension may be either an extendable
or non-extendable design but shall be a single
tiller with one end connected to the crossbar in
the same location as the factory supplied tiller.
THE TILLER EXTENSION SHALL BE MADE
OF A NONELECTRICAL CONDUCTIVE MATERIAL
ON ALL NORTH AMERICAN REGION
BOATS. NONELECTRICAL CONDUCTIVE
TILLER EXTENSIONS ARE RECOMMENDED
ON ALL BOATS WORLDWIDE.


I've always used the stock tiller (non-extendable fiberglass) on the 14, 16 and 17. Most of the other racers do too.