I have an older model ZZ (2016 I think) and purple scandere. Even when the rope was brand new I never experienced any creep in a MRS or SRS configuration. Very smooth combo IMO, and smooth as butter SRS with the rope wrench.
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The biggest complaint I have is the bounce. More stretch than I like for a SRS ascent, but pleasant to work a tree on otherwise.
I don't find it flattens anymore than my blue moon in any device I've used them both with: BDB, ZZ, HH2, wrench.
Perhaps the best 24 strand I've used is "Ruby" from Elevation Canada. Stays round under load and despite being advertised as 3% elongation at 10% break strength, it feels to me more static than blue moon.
https://elevationcanada.com/shop/ols/products/ruby-115mm-climbing-line-with-1-hand-splice-eye
Not sure if this helps you in your search for the unicorn rope or not. Having a rope custom made to your specs sounds cool, but expensive and impractical. As
@Jehinten says, might as well buy the whole 1200' and cut it to lengths you'll use for climbing.