Great Lakes Skipper is a manufacturer liquidator, and I think they have OEM original canvas for your 25. At least they did this spring.
Let me take a look.
There you go:
http://greatlakesskipper.com/mako-12...1-2-white-blue
Looks like they have only white/blue right now though.
(Says Mako, but its for the 25 Seacraft)