I’d say go for it. Make sure the welds are good, and try to use the same material. From a statically loaded position, your new frame will be able to hold more weight on the end then the stock one, due to the torque moment (Force x Distance) being reduced. I think I personally would add in a few cross members, possibly an X brace to tighten her up some. Possibly add some decorative cross members, which can also aid in support. Them bikes look great.
Oh and I’m not an Engineer yet…I should be in May though.