You have access to a lathe and/or mill and/or machine shop? I'd bet there's some weight to be lost, but idk where would be the best spot to trim. Also, there may be surface hardening and/or heat treatment that may help, but that's a little beyond my experience. Any weight you take off will be banking on a decent safety factor in the OE design because that's what you'll be reducing when you trim material. Forged wheels that are designed to be light weight are really the best way to cut weight without losing strength. Those are pricey though!
Definitely interested in what you come up with! I like the build a lot so far.