It sounds like choosing the Larian vault is the best way to go then, if you get a Steam key and DRM free download. I initially set my Kickstarter reward to Steam, then changed it to GOG when I bought the Collectors Edition since comes with two Steam keys. I'd like a DRM free backup and I don't need three Steam keys.
In another post, it was said the CE boxes won't ship until later this week and it might take another week or two before it gets to the US. So if I don't want to wait a week or two to play it, I need to switch my KS reward to Larian Vault.
I was thinking of waiting for delayed content to be patched in before starting, so maybe by the time my box arrives that update will be out.
I assume sometime today will be the cutoff to change it? I just checked, and it's still giving me the option to change it.