TG20:08 has a light duty ( 0.75 kN/sq.m. ) suspended platform on wires which has a maximum grid of 2.1m, which would be the same for a birdcage.
The bay centers are determined by the ability of the ledgers to take the loads in bending.
If the grid spacing was reduced in one direction to say 1.0m then the droppers may be increased to 2.5m in the other direction, but this would depend on the live load on the deck.
TG20:08 states that slung scaffolds should be specially designed.