This house has a bedroom inside a large turret. The question is: what is the best way to prep a circular room for plaster? We've gotten several different opinions.

Can we put one skim coat of regular mud, and then one coat of diamond with glue onto dry wall? Or, is it necessary to use blue board for vapor barrier? All our plaster will be about 1/4" thickness. If we don't have to use the blue board, we'd rather not, because it will be more difficult to work with in a circular room. If we can use two 1/4" flex board and thereby create close to a perfect circle, this would be easiest. Otherwise, we'll have to use regular 1/2" blue board and either wet it or score it.

Thank you for weighing in and helping us make the right decision!