G&G, I've never shot an IDPA Match, but I've competed in USPSA matches many times. If you're matches are held outdoors, one thing to consider when shooting into the sun (or even into bright lights on an indoor range) is the amount of smoke present with cast lead bullets. It can obscure your view of your targets in some cases. If that situation applies to your shooting, you may want to choose a jacketed or copper-plated bullet for your competitions. Much less smoke with those.
I've found a good combination for my .45 ACP's is either Zero or Rainier 230 grain FMJ's over 3.8 grains of Hodgdon's Clays (not Universal Clays - just "Clays"). Accurate load, reliable, and very easy recoil - since Clays is a very fast-burning powder. If you try it, as with any load, start at a bit lighter volume and work up to it, monitoring for signs of excess pressure.