Keel, I am not going to argue this anymore.
You surely have heard about Selden masts, right?
Please allow me to redirect you to their shroud adusting manual.
PAge 30
PAge 31
PAge 39
I am sure your calculations are all correct and such..I got this this morning off the net by googling tension shrouds, and found this manual.
There are several more with the same instructions.