Hey Essington,
There's nothing like other people's problems, eh? So here's my two cents while I stew on my own problem/s.
A few years ago I had a dock line with a knot that WOULD NOT be undone. I had new dock lines, so for fun (it's all fun
I decided to cut the old line while under tension and see if it was *really* like the danger everyone blathered about.
OMG!!!
A T-storm was blowing quite predictably violently, and I had a new dock line in place, and all I did was *touch* the old dock line with a sharp knife and THWACK - it friggin' parted like any bat out of hell fantasizes it could!
It parted so fast and easy with just the TOUCH of a sharp blade after that I decided I would NEVER have synthetic rigging on my boat. It was so impressive I am Still on the negative side of even carrying dynema as a spare shroud.
You don't give enough info about your boat or its intended use to go into any detail, but given its size and make one would guess you *really* don't need to bother with the danger, expense, or nuisance of dynema.