I think some TBH have different width bars, slightly thinner ones for brood. I'm guessing the comb built for honey stores is thicker. That's the impression I've gotten from doing a lot of reading but when I watched videos of people building their own TBH, all the bars are the same size.
Here's a video for building the bars... Top Bars
You can also check youtube. There are hundreds of videos of people building and using TBH. Most of the way people built the bars are simpler than the above video.
Good luck with your new hives