Regarding entrances, I think they are a bigger deal for Beeks than bees. As I said while you were here, Beeks have been tinkering and debating for hundreds of years and yet bees thrive in spite of them.
My two cents regarding top entrances would be to remind you that they are mostly advantageous on Langs so that the bees don’t need to navigate up through several stories of brood and supers to store their goods. Travelling horizontally that becomes somewhat of a moot point.
Drill two or three ¾ inch holes in the side (high or low or both) and be done with it, then you can plug one or two of them if you choose to. Put a couple at each end and see what works best. I don’t think the bees will go in under your top as you would like for them to. Mine wouldn’t leave the unused section past the follower and died there so I sealed it off.
Don’t give them too many bars too fast. Keep them tight and watch for SHB until they build up numbers. Do you have bees yet?
Regards and have fun!