Hi Tim
You know the blue anodised arms that you can adjust, either on the beach, or with another type of adjuster barrel you can change them on the water, but this requires capsizing.
Goodalls asking nearly $400.00 for them, Binks I think work out to around $320.00 and everywhere else seems to be somewhere in between. The stainless steel mast collar may not be strong for cats and therefor most cats have a stronger one made for them, very easy, just a little bit more meat.
Regards