I couldn't shave it b/c I had the SRP model. Way too much mass to deal with. Heavy too! I'm sure that some out there could have made it work but I chose the lo-pro GB route. Tons of people use clamp-on blocks and they come installed on many high-end offerings.
As for the Troy Alpha, it does use the standard barrel nut.
I hear ya though... Sig did not want that GB to come off...EVER!!!
https://lh3.googleusercontent.com/-X...011_004432.jpg
Railed GB weighs in a 1/2 lb (when it is complete). This pic does not show the cut off bayonet lug and sling swivel lug.
https://lh3.googleusercontent.com/-o...011_004453.jpg
Check out how deformed the rail is. I had to beat on it for about 10 minutes after having it soak in PB Blaster for half an hour.
https://lh4.googleusercontent.com/-C...011_005351.jpg

