Moving from small goods to holsters/sheaths

I'm about 4 months in to my leathercrafting journey, so far I've just made small goods like wallets and clutches. Pretty soon I'd like to try my hand at working on thicker projects like knife sheaths, holsters, and belts.

1. Are there any tools that would be necessary/recommended that I likely wouldn't have purchased for crafting small goods? I have pretty much all of the basic hand tools for the items I normally make.

2. For a functional piece like this is there a different approach to saddle stitching that needs to be considered as opposed to a wallet?

Any advice or information for someone completely new to this side of the craft would be much appreciated.