I buy from west coast. In my experience, they aren't terribly informed about screenprinting. I can't say that they will be the same where you are though, I hope it's different. When I first went in to get some samples, the sample room guy asked me why I wanted uncoated paper, implying that he thought coated would surely be what I was looking for. Aside from that, they have been pretty helpful and the sample room has been really helpful. I kind of doubt that you will have much looking for the specific things you mentioned. This is one of the suppliers that is roughly four times the price that I am getting at midwest for sticker stock. Maybe I should negotiate, but that's a long way for the price to fall.
A small complaint that I have is that I like to use the estore of my suppliers as much as possible, to at least look up the prices before I phone in an order. West coast's store is pretty sparse. The major things that I need are there, but the specialized papers are generally not represented on the estore.
Well, I can't recall if this is a thing or not, but I think they may even shut down the estore at night. I just went to check if they had the stuff that you were looking for and I can't connect. I tried in another browser and the spot where the login fields would be is blank.