The higher you go, the shorter the throw. And yes, I turned the shift lever 180.
I cut my metal plate back a lot, and then re-installed it. Some folks have removed it completely, and just but the four bolts back with ewashers to hold down the rubber boot. But that does give a bit more air/noise leak into the cabin. ( or so the posts say.)
I measure from the top of the perrin unit, to the top of the fat section of the shift lever that it attaches to. 54mm was as high as I could go in my car, but every car is a little different. I'm going to move mine around a bit, and see what height I like best.