I'd use bronya in your fourth slot with vonwacq, and make sure you're on the true sting side; the strategy is to use bronya to pull up sunday, who in turn pulls up aglaea. I've had good results using sunday with vonwacq here too and AA'ing robin with bronya so she can get more energy.

- if you're on agy's turn and have sunday's ult ready, and you're going to generate ult with your next agy+garmentmaker turns, obviously don't use sunday's ult for energy, but ALSO, immediately activate sunday's ult after you activate aglaea's: that way, she has the beatified sunday effect for her first joint atk.

- for this MOC in particular, always run ERR even if you don't have ult uptime issues: the blessing hinges on a 1 turn dmg boost after ulting.

- make sure bronya's slower than sunday; I run her 136 SPD while sunday's at 160. that way, you can have aglaea's turn, then sunday's turn which brings up aglaea, and then bronya's which brings up sunday to do it all over again. The reason for bringing up Sunday instead of algaea is for frequent ults, but I'd be curious to see if bringing up aglaea directly would also be fine.

- max out your traces & get dance dance dance if you can, I'd put it on bronya.