Hey EME cousin!
From Australia, for all Minimi, we only use one gauge for HS force wide, a no-go at 37.375mm. ADI (Thales) produced in Lithgow, NSW. Very simple, used at all levels of repair, including FTR.
Australian Minimi are known as the F89A1 LSW, and utilise FNH recievers, some Cdn NSN parts, some US NSN 00 and 01 parts, some FNH NSN 13 parts, and many ADI manufactured parts bearing Aust '66' NSNs, including a unique Aussie heavy barrel. US M249 butt, and MAG 58 flash suppressor. No front sight on the bbl, and a generic F88 1.5X optical sight on a Picatinny rail. No rear 'iron sight at all. Also the hydraulic buffer is used.
We also use the Para, but this gun is an off the shelf FNH buy.
F88 (Austeyr) FOW uses 37.41mm No go used.
Go gauges are not used in Austeyr and Minimi, period.
Hope this answers some of your question WRT Minimi.
As for the school, in Canada, its CFSEME, yes at CFB Borden, about 80km from Toronto. In Australia its ALTC (formery called RTC located at North Bandiana) at Latchford Bks, Bonegilla/Bandiana, which is near the NSW/Vic border towns of Albury-Wadonga.
Regards,
OWDU
Armourer