I use Edelweiss Sella rope which is 8.5mm. I think it is a half rope like the Sterling Duetto. I think the half and twin ropes are supposed to be used in pairs but I am not really sure. 5400 lbs breaking seems to be required for arborist rope. Dynamic rope never seems to report a breaking strength and I don't know why. I used 8.0mm dynamic rope for a while and read somewhere the breaking strength was around 2200 lbs. I felt a little uneasy using it but never had any problem with the Safeguard using it. I feel much better on the 8.5mm rope which a few users have described as being more like 8.9mm rope. I don't think the breaking strength is 5400 lbs but it should be closer than the 8.0mm. That is about all I can say. It is your choice what rope to use.
I did a one sticking video a couple days ago where I used the Sella rope.