turing . . . eer turning test for [rear] axle ratio identification

i've seen the turning test generally reported as half the ratio. i.e. double the driveshaft turns obtained by one turn of the wheel to get the axle ratio.

not sure why that is, assume maybe the gear for the non turning wheel is taking up 1/2 the motion?

would this test work on an autolock limited slip. can you slow turn the one wheel without locking i assume? would double the result hold? is there a simple in situ test to identify non-electric limited slip?

By axle code B07A I've got non-locking 4.3 which coordinates with turning test results of about 2 and 1/6 turn of driveshaft. don't know that it would be problematic if I got an LSD as long as the ratio is right.

I've got a slight bend in the axle housing that is resulting in about 1" of toe out at the front outer dimension of 265/75 R16s (about 31.5" diameter according to charts and my tape measure) consistent with rotation so I put it down to bent housing, not axle.

Doesn't appear to be set up for any shimming to accommodate any minor deviance from parallel, nevermind an inch. So I'm gonna to use straight edges on potential replacements to check for parallel front to rear and top to bottom. Should I expect spot on or within what range at what radius?