RE: extensions and bases
yes you remember correctly, it will be US cup in any case. And aluminum in any case.
I have no problems with plastic, it should be far more reliable than metal if sizing is correct. I think it's rather about weight, as I expect metal (Streamlined) pulley assemblies to be lighter than plastic ones (Chinook). But I don't think it would be a great difference. By sure, the QuickSix is more compact and elegant than the Chinook big plastic block, you could say it is more "streamlined". But the pulley orientation, as you pointed out, is aligned with the sail pulley, not a big problem but I am used to the other way. I also suspect that having the pulleys aligned would result in some torsion, not important but maybe annoying.
In the end and all considered, as I see there are no concerns about Chinook's reliability, and since prices and availability are much different, I will go for Chinook.
I agree with your thoughts about Maui Sails. They have a straightforward, no-nonsense, solid design approach that is just what is needed for any windsurfing hardware component. Only I think that, differently from booms, in the case of extensions there is not much to make better relatively to existing manufacturers. Maybe...
non c'è bisogno che ti dica che Talamone a Luglio dovrebbe funzionare e quest'anno con la terra che si è raffreddata poco ci sono aspettative di termici pazzeschi...
Conosco Massimo, spesso monto la vela proprio dalle sue parti. Dovrebbe avere ancora qualcosa da vendere, ma non amo il sistema Euro-pin.