From the WBAS Handbook:
•Holsters and magazine pouches must be of traditional or military design and
made from traditional materials, (e.g., canvas or leather).
• The holster must cover the entire length of the barrel and slide from the muzzle to
the ejection port. No “open front” speed holsters allowed.
• If a holster has a flap or strap it need not be closed during competition.
• No metal or plastic “competition” type equipment allowed.
• No shoulder or cross-draw holsters may be used during competition.
•Magazine pouches must be worn on the opposite side of the body from the
handgun.
•Magazine pouches must be worn vertical and conform to the shooters body (i.e.,
not tilt out from the shooter’s body).
• Magazine pouches can hold either one or two magazines.
• At least two inches of the magazine must be covered by the magazine pouch.
•The flat side of the magazines must be parallel to the body. Magazine pouches
may not hold magazines with the thin edge next to the belt. The flat side of the
magazine must be parallel to the belt.
•Pouches holding one magazine may be sewn directly on a belt but must hold the
magazines in the same manner as other magazine pouches.
+1 what August said.
In looking at the photo of the rig on the website, it looks fine to me. It appears he has designed a holster for the 1911 and put it on a standard standard boscadaro belt with often seen 10 loops for pistol ammo. My only comment would be that those are just taking up space you will need for more magazine pouches, but that's just me!