[sharpiel]

Heya Matt.

If you go back and have another look at mine you'll see that between the top spreader screw and the rigid lower spreaders I put an adjustable tension chain. I can vary the tension applied by the chain for optimum benefit.

The reason is to provide a tension inwards on the lower added spreader points to offset the outwards tension generated by the original SW spreader up near the top of the tripod. Because you and I both made our bespoke lower spreaders hinged to allow fold up for transport it doesn't really provide a lot of extra benefit. It's the chain that applies the opposing tension between the two spreaders that really increases the system rigidity and thereby helps reduce vibration and reduces the inherent instability before the modification.

I would highly recommend you add the chain between the spreaders with a tensioning ability to wind the chain upwards to pull the legs inwards at your spreader against the top spreader. Without that I think your efficiciency will be markedly reduced. Once set the chain tension never needs to change. The tensioning is independent of the upper SW spreader screw. When you fold the tripod away the chain tension releases until you reassemble next time and then is re-tensioned automatically when you tighten the top spreader up as you would normally.

I only built the lower spreader spider to accommodate an anchoring point for the tension supplied by the chain.

Cheers