I'm using whatever I happened to have on hand, can't say in detail off hand but could track it down if folks are interested. Regarding the strengths, fishing line when catching a fish is subject to sunlight and friction and ... Though the weight is just about weight and not accounting for that, I imagine in practice because people are lazy and buy the strong one that's small there probably is more strength then weight says.
More importantly when hanging lights I usually have multiple, independent, strands and multiple loops. On a light with 2 mounting points I'd have one line on each side, with each routed to the top and looped through the bottom. Double lines splits the weight across both, and though the looped doesn't make one line fully independently two, it does reduce the load carried by any part of the strand.
In that case a 5lb light hanging in that manner would have 2.5lb on each line, and each vertical piece supporting 1.25lbs. Pretty easy to oversize and have low, IMO, risk on it.
The main complication I've encountered is that initial setup can be kind of tricky, getting everything evened out.
Pics I'd shared in the past, coincidentally last Christmas: