Happy to see your post and planned direction, Chris.
For the Burleigh Co. Cup, I did:
SSB 1 & 2 Mid
Sustained Power Build
Century Specialty.
It served me well for the 75 miler, and 4:40 time. I was around 3.5 to 3.7 w/kg at 145 lbs at the time.
https://www.trainerroad.com/career/chader09/rides/34337047-burleigh-county-cup-2018-gravel-race
I think that same approach works for you even if you opt for the Sippy Cup.
I may switch up to General Build and Rolling Road Race Specialty this season. I might shoot to stay with the lead group as opposed to my steadier approach of 2018. I’m still considering the options, but the choice goes down a lot to how you want to ride or race it.
The race was super fun and I’m excited to come back in 2019.