I use Ringwood a lot and have never run into problems with it stalling due to a closed fermentation environment (this includes 5 gallon batches in a 6.5g carboy). I usually get around 75% attenuation from this yeast. Also, I have had the best luck fermenting this yeast around 65-68F for a few days before bringing the temp up for a nice long D-rest. After 3 weeks in the primary the beer is crystal clear and very tasty, nice mild esters without the butter. I make a killer brown ale with ringwood, even won me some awards!