I have a 92FS and a 92G Elite II which uses the Brigadier slide.
Some caveats. The EII has front slide serrations which remove a tiny bit of metal compared to a standard Brigadier slide. My EII wears adjustable sights which are probably slightly heavier than the stock sights. Both of my slides are stainless steel.
Here are the stats from my measurements.
Standard 92FS stainless steel slide weight: 11.3 oz.
92G Brigadier stainless steel slide weight: 12.0 oz.
Standard 92FS stainless steel slide thickness: 1.11"
92G Brigadier stainless steel slide thickness: 1.165"
So the Brig slide is about 0.7 oz heavier and is about 0.055" thicker than the standard slide. It is unquestionably heavier and bigger than the standard slide, but we're talking less than three quarters of an ounce heavier and just a hair over half of a tenth of an inch thicker.
For perspective on the weight comparison, you can change the weight of the gun more by carrying 147gr defensive ammo vs 115gr defensive ammo than by switching slides. The slide change affects the weight by 0.7oz while going from 115gr ammo to 147gr ammo would change the weight of the fully loaded gun by 1.17 oz.