For carry, I use a leather buttstock carrier. It has loops on the offside and, I believe, holds 7 cartridges. I also wear a culling belt which holds a bunch more.

I've practiced reloading both ways - holding spare rounds in my fingers, as well as just trying to prefect a "rapid reload" technique that has me pulling the next cartridge from the carrier with my right hand as soon as the ejector has propelled the spent case from the chamber.