We had a simple job last week of lifting in a meaty RSJ, four men at each end, English speakers one end Polish at the other. (not by choice but they dont like to be parted...). When the forman asked us to lift a bit they all ran to the LEFT! Not so clever with 700kg of steel above your heads...
Its fine to use board adhesive, the only trouble is when you come to finish your mitres and joins. The board adhesive shrinks back too much and will not finish your mitres and joints as well as coving adhesive.
Hardwall is the best backing for multi finish on the market. As long as you get a shift on with floating your walls early in the day, you can skim them all up a few hours later. So solving your suction problems when skimming, huge areas are attainable.
Ps. Dont leave it more than 24 hours...