G'Day Fella's,

NitroX, my best advice, would be to attend an IPSC shoot, and have a look at what is being used, and ask these folks for advice.
The reason I suggest this is, I imagine you will see a wide variety of types and styles, of both Holsters, and Magazine Pouches, that are considered acceptable, for use in IPSC.

Also, are you Right or Left Hand dominant?

I'm not 100% sure but the STI, Trojan, "may be" slightly different, from your average 1911 ........?
So confirm this, one way or the other, before you start spending $ on any holster.

I suggest you have at least 6 magazines (and a couple more would be handy), and Wilson Combat make The Best magazines, for Single Stack 1911's!

FYI- As a starter, www.unclemikes.com make good serviceable Kydex Holsters, and mag pouches, to suit normal 1911's, (and other pistols).
You should be able to order these, thru your LGS.
Other brand options, include Hellweg, Blade Tech, Safariland, Galco, etc, etc.

Can I also suggest/ask, in Oz, the .38 Super, is almost exclusively a Handloding Only option!
So I hope you already have some "Crackers" for it?

Hope that helps.

Regards
Homer