Re-Loading 357 SIG

357-SIG is a fairly exotic cartridge in realms of Non-Government agency shooters. As such only a few folks have published any “original / experimental” Load Data.   The various commercial data reference books all present; SAFE, Conservative and highly caveated  recommendations. So off we go into uncharted (‘till now) territory
REF: 347 SIG cartridge size chart .. in Millimeters My quest is to load “Standard 38 Special / 357 Magnum Bullets into the 357 Sig Shell Casing. The only recommended Bullets are the Standard 9mm Parabellum at: 0.355” Diameter and a Designated 357 SIG Bullet of 0.356” Diameter. The Standard 38/357 bullet diameter is: 0.357
Load tables for Accurate Arms No. 5 powder only go to a 147Grain weight. My plan is to use a 158 Grain Semi-Wad-Cutter. Measured at an average diameter of: 0.3569 over 100 samples.
Non Variable components: Gun-Sig Sauer P229S, AA No. 5 Powder and 158 gr SWC bullets.
The variable is Powder Charge
Extrapolating data from Data Ref. sources, I have established a range of loads to try. Guard-Banded at the top end; 7.7 Grains  Setting up a set of Trial Loads: 7.0 gr to 7.7 gr.  This allow for +/- tolerances of:  a) Powder Mfg. (3% consistency batch to batch) and measuring scale +/- 0.1 Grain.