I heard from Rabbi Chaikin, who compared the reasoning to Eruv Tavshilin.
What other opinions are there?
Halachically, if you use the hetter of 12 months etc. it's the same thing.
If Gebrocks is only okay (and encouraged) due to completing the entire Series of Chesed and the מאיר גילוי הארת המשיח, you wouldn't necessarily have those insurances on the 7th.
IOW, if you're looking for a Halachic basis to allow, you can definitely do it on the 7th. If your looking for a Kabbalistic basis to encourage, I don't know if those apply on the 7th.