imho. - do nothing for 8 to 10 days from the day the hives were combined. Why? Because: :
1) it will take that long for the bees to sort themselves out and organize the heart of the nest and the stores, as a single colony. They will move alot of stuff around in there. Takes them a bit over a week to get that done and to be happy with their house.
2) it will take that long for the bees to decide whether THEY want to run with 1 queen or 2 queens, and ultimately which queen they like better.
3) it will take that long for it to be easiest for you to see what the bees have decided to do.
a) If they decide to go with 1 queen, it will take that 8 - 10 days for the eggs from the queen they dispatched to develop into larvae. There will be eggs in the box of the queen they kept and there will be no eggs, only larvae, in the box that they offed the queen.
b) if they decide to continue with 2 queens, there will still be eggs in BOTH boxes 8 - 10 days later.
As for whether you yourself the beekeeper wants to run with 1 queen or 2, it is quite simple. With the excluder the bees are more likely to tolerate 2 queens. Without the excluder, the queens will eventually end up on the same frame and there will be natural selection of 1 of the queens made by the bees. In other words, if you want 2 queens leave the excluder and you might have that outcome for a couple weeks to a month. Ultimately it is a temporary situation. If you want 1 queen, just pull the excluder and let the bees decide which one they want to keep.
All above is information to think over and will require minimal at-the-beehive effort on your part. You really do not need to do much. All you need to do is decide whichever outcome suits you - 1 queen or 2 queens. At the hive, your only actual planned action would be to leave the excluder or to pull the excluder. The rest of an inspection would be just you gathering info to try to figure out what they are doing. What you would actually do with that information, in all practicality - is nothing.
Hope that helps!