That is like asking how long is apiece of string !
Flown 17 hours lifting this week in The Peak District, have flown the following this week
Dumpy bags of brash each weighs around 125 kgs taking 4 at a time on a carousel (3 hooks ) on a 40 ft line under Hughes 500
Result
3 bags are put on one to a hook with a 6 to 8 ft strop the load will spin a like a bugger
4 bags stropped in pairs one pair to a hook ( 4 bags in total) load normally stable
5 bags 2 pairs and a single then load will sometimes spin seems to depend on the single bag if it gets into the airflow on one side
Pallets of fence posts ( 2 m ones load 2 choke stoops going to single hook) in 450 kg loads, they all seemed to spin could have something to do with 40 kts of wind !!!!
Planks ( 4m )with gate posts, spins all over the place !
For James May, Lada car spins so need a windsock to keep it straight ! Also helps tip car over when dropped form 500ft so it hits nose first !
Hope that helps