Drywall mud between isomax walls

Hi, Working on the drywall stage of my attic studio. We've decided to hang single layer drywall from isomax clips and channel in the larger continuous areas, in combination with double-drywall and green glue in other, more complicated areas. My drywaller is very wary of my instructions to leave that 8th of an inch gap between the adjacent angled walls and is concerned that, once mudded and taped, the joints will crack because of the movement of the walls. Is there a standard procedure for how these joints should be finished? We're going to fill the gaps with silicon caulk. Then I assume that then mudding them over and taping them is O.K. He fears I won't be happy with the finished product. Can some of you experienced hands verify or dispel? Is mudding the floating walls to each other or the hard-nailed double drywall going to completely defeat the benefits? Thanks, Chipal

you need to fill the gap with backer rod then acoustic caulk. joey

Thanks Joey! I understand the gap should be filled with acoustic i.e. silicone caulk. But after that, for the finish coat, can mud and tape be used over those joints without disturbing the acoustic isolation properties?

yes