Looks like you already have the answer. Wonder why you bother asking? Also, your question is not specific enough. Best formula for what? For speech in noise? For music? For overall natural sounding perception?
I know that you did say for sloping hearing loss (precipitous loss), but most people have sloping hearing loss, so that's not specific enough. If you had said for cookie bite type hearing loss, then that's more specific because cookie bite losses are not as common. Or for reverse ski slope loss, which is also not as common.