Plastic Conical with 2" opening

I just picked up an ace rotomold conical with a 2" drain and am trying to figure out the best way to go here. I would like to harvest yeast, so I can see the benefit to having a larger diameter at opening, but 2" ball valves are a bit beyond what I want to pay. Is there any reason I couldn't get a stainless bushing to go from say 2" to 1 or 1.5 inches, would it leave too many crevices for nasties to grow? Or should I just buck up and spend the dough on a 2"?

Thanks for the advice!

Ideally the less pieces you have, the better. They will all need to be cleaned.
There is a 2" triclover stainless ball valve on Ebay that you might want to look at.
Right now it's pretty cheap.

Thats a good one, I might have to put a bid in. The other thing I'm starting to see is that by the time I purchase all of the SS parts to accommodate a 2" valve on that (camlock fittings, etc.) I'm only about 20 bucks cheaper than doing the same thing with sanitary fittings from brewers hardware. I may just pony up and go the sanitary fitting route.