Spreader length

[Helios]

Hi All..

Is it true that in a two spreader rig, the lower spreaders are typically 85% as long as the half chain plate width, while upper spreaders are typically 65% of the half chain plate width?

I was told that this is true when the lower spreaders are about 1/3 up the mast from the deck, while the uppers are 2/3 the way up.

Thanks...