HH mod - double structural ridge line. Opinions please.

[Thijzzz]

Hi all, I'm still mostly lurking and whenever I return from a trip I keep thinking up ideas to make my setup better.

So here's an idea I came up with: I wanted to replace the original lines with about 1 ft of 5 mm prussik cord (load capacity 580 kg / 1280 pounds) and end in a cinch buckle. And work with webbing from there.

I thought this version would give double strength and make it easier to tighten the knots evenly at the buckle.

Pic 1: Overview

Pic 2: Detail of wrapping with knot. The granny knot's there to hold the wrapping in lace. White mason's line is the internal ridge line.

Pic 3: 1 prussik for the fly, 1 prussik for underblanket attachment.

Pic 4: Detail of knots on buckle.

Now here's the important question: If I tighten the buckle knots, will it hold? Or should I add a granny knot in each "leftover" end?

Opinions please!