In a different thread I showed my setup between two poles that were 16.5' (198") apart.

Bubba said that for that distance the straps should be 7-7.5' high. As it turns out, a strap height of 7'3" (87") would have - with all the other measurements remaining the same - according to my math - given me the ~30* angle that I was looking for on my straps. This works out to:

(16.5/2) - 1 = 7.25

Is this relationship constant, i.e., can this equation (where S = span and H = height of strap placement):

(S/2) - 1 = H

be used to determine optimum strap height for a given span? If so, is the 1 value constant or is it a variable, e.g., strap length from tree to whoopie connection point, etc.?