Plasma rope

[Brion Toss]

Hi,
Cortland makes great rope, in my experience, but their plasma might not be ideal for standing rigging. For one thing, at 23,000lb break, it is about the same as 9mm Dux or HSR. 7/16" is rated at over 31,000. This makes for a higher relative load, thus more creep.
Next, even if it is the right size for your boat, the lack of prestretching will be a problem, and a temporary lashing, if that is what you are proposing, will be a needless bother. But if you can pretension appropriately on the ground, before splicing the second end, the set might not be an issue, and you can just hook up directly.
This leaves the question of size, and 11mm anything HM seems too large to replace 9/32" wire. Maybe 9mm, maybe even 8 would be better.
Fair leads,
Brion Toss