Ten metres of yellow Zing-it for the ridgeline and three 55cm lengths of black Zing-it for the Prussik loops. Splicing an eye in one end of the ten metre length of yellow was straightforward. For some reason the black zing-it was much harder to work with and the Prussik loops took a bit of swearing to get to behave.
Prussik loops work best when the loop is of a smaller diameter than the main rope or line. In this instance the two are the same diameter and then there's the fact that zing-it is very slippery. VERY slippery. This means that rather than the usual two or three wraps four or more likely five wraps are needed to ensure that the knot holds. In the event I found I needed six.
And yes, it works

The combined weight of the ten metre ridgeline and the three Prussik loops? ... wait for it ... wait for it ....
5g!
Yes, a whole five grammes and not a lot of volume either.
Add 5 x 1m, 5 x 2m and 1 x5m guy lines (I can mix and match according to the site or extend as necessary) and the sum weight of all the lines is 25g. For the summer asym tarp I'd only take 2 of the 2m so the weight would be under 10g with another 10g for the two pegs. Not bad.