When I shoot revolver IDPA and I can use Safariland Comp IIIs (such as when shooting a Colt Diamondback or Smith 19), I use the pricey but excellent Safariland three-place carrier. Since IDPA only allows two speedloaders on the belt, I just use the rearmost space for the initial load-up.
They have one for the L-frame 586/686 series, too.
This has not run afoul of any rules interpretations yet.
If it's a Python day, then I use the open spring metal carriers with Comp IIs, the mid-length ones.
In any event, I strongly urge you to try a couple of the Safariland Comps, especially the IIIs. They are superior to the twister loaders by a wide margin for competition. In fact, I simply stopped competing with wheelguns for a couple of years because of how discouraged I became with leaving my new six laying in the carrier, or worse, sprayed on the ground.
The Comps are much more positive and secure, not to mention simpler and faster, just what you need when you're trying to go fast.
They're not expensive and you really only need two for IDPA. You can use the old ones for the initial load and for the pocket backups.
Bill