hardibacker joints and screws?

[mazears]

I've studded one wall of my bathroom with a combination of moisture resistant plasterboard and hardibacker (shower area). Other wall of shower is solid brick and i've screwed hardibacker to this using zinc woodscrews/plugs - Will this be ok or should i have used aquapanel screws (would be a pain to unscrew everything again!) I used drywall screws for the studded wall (combination of mr board and hardibacker).

Also i've tried to fit all board joints tight together. As they are all now screwed to the wall/stud, should i now open up joints slightly (grinder/stanley knife?) in order to fill/tape joint before tiling + can i use normal plasterboard tape?

 

[tictic]

the brick wall..was this studded out for b/boards?
or did you dot n dab with flexxy addy then mechincal fixings?

as for board spacing,fiba tape it will be in m.i.