I too thought of the more rigid line for the sheet. My question is safety related: can you safely (quickly) drop
your main sail without having to undo your “sheet”? I’m guessing it would be arduous to undo it all then drop your sail in a blow.
I would have 2 lines. Maybe even by cutting down an unnecessary long halyard.
Just a point in sailor speak, lines are characterized as soft or stiff when talking about flexibility and hand, how the line feels in the hand. Sta-Set X is an example of a stiff line, it does not run through blocks easily because it doesn't bend well, it is hard on the hand. Regatta braid is an example, it is soft and fuzzy, very easy on the hand and runs through blocks well.
Line is also characterized by stretch, generally high stretch or low stretch, with low stretch being preferred for halyards.
These characteristics are on a scale and not absolute values, although for stretch rope makers do specify a value.