Redoing ceiling - batten / frame question

Hi everyone - this is my first post!
<o></o>
I’m looking at putting up a new plasterboard ceiling in a room that measures 5m x 7.5m. The room already has one of those old horse hair plaster ceilings which I would normally like to leave in place. My normal method for redoing a ceiling is to just put up new steel battens (topspan or rondo) perpendicular to the existing timber joists, then fix the plaster board the normal way.<o></o>
<o></o>
My problem with this room is that the existing timber ceiling battens span in the same direction as the long edge of the room. So if I run steel battens perpendicular to those I will end up having to flush a butt join in the plaster board, which I’m not real keen on doing if I don’t have to.<o></o>
<o></o>
Can I run one set of battens perpendicular to the existing ceiling joists, then run a second set of battens perpendicular to those so they span the longer direction of the room? This would allow me to use 5m long sheets of plasterboard and flush the normal way.<o></o>
<o></o>
If this is possible, should I use steel battens for both, timber for one and steel for the other, or another combination?<o></o>
<o></o>
Any other ideas on how to avoid flushing a butt join?<o></o>
<o></o>
Any help appreciated.
<o></o>
Thanks<o></o>
Archer<o></o>

I thought the biggest sheet of gyprock you could get was 4.8m. I certainly wouldn't want to put up a celing sheet that size without at least three pairs of hands or a sheet lifter.

You can get 6m ... wouldn't want to do that on your own!!