I think: a continuous ridgeline cord will add to the wind worthiness of your tarp.
with a flat ridgeline tarp, a CRL cord under the ridge will help support the whole structure.
with a cat curve ridgeline, a CRL cord is prolly unnecessary. although the use of one couldnt hurt, you just have to let it sag a little if you tie off the ridge first and the corners second.
this depends on the depth of the catenary cut, and the angle of the side cat cuts.
my opinion? i prefer a straight cut ridgeline and a full cord running under it, and side panel pullout (tieouts) for a variety of pitches, like you would find over more than one hammock. also, zing it or lash it works fine. amsteel is a bit much...
p.s. i use prusik knots like many others on the main ridge line to easily adjust the tarp. its very quick to pitch in this manner.