When should I check on a cast swarm?

[Do224]

I caught a small swarm 11 days ago. They only covered a couple of frames so I’m assuming they’re probably a cast.

I’ve given them two litres of 1:1 syrup on day 3 and vaped them on day 7. Other than that I’ve left them alone. At what point should I be opening them up to have a look? Anything else I should be doing/be aware of?

 

[Erichalfbee]

Look now.
I have one similar.
No brood and all the syrup stored in the one drawn frame they have
The bees are all fanning like crazy on the top bars so I'm sure they are queen less. They are on the potting shed roof and they will be united with the established first swarm next to them