Some may be tired of my continually recommending forum sponsors but I personally always want to first consider doing business with those vendors who do sponsor this forum.
With that said, I still think the best place to buy wiper blades is RVUpgrades .com. They not ony are iRV2 sponsors but the owner founded this forum. That aside, RVupgrades is one of the best online vendors I've used to purchase things for RVing. They are fast shippers, have very reasonable --if not the lowest-- prices, and have excellent customer service.
They sell the Wiper Techologies blades from Diesel Equipment. They're excellent blades. They're heavy-duty and are specifically designed with motorhomes in mind. They also have a catalog that covers just about every motorhome out there ...
go HERE
If you go to page 28, you'll see that a 2011 Newmar Baystar will take the Wiper Technologies part #WT8-32
At RVupgrades, it's $25.53
Wiper Technologies WT8-32 J Hook Wiper Blade - 32" at RVupgrades
Yes, it may be a bit higher than buying an Anco, Trico, etc. at Napa or Walmart, etc. but I think you're getting a far superior blade at a price that probably can't be beat anywhere else for the same product.
I suppose you could go to a shorter blade if you wanted to but I think I'd want a 32" in your circumstance.