I have not tried those brand of cubes before. I used the brand/type that BedBath&Beyond sells. You just want to make sure that the squares in the cubes are small. If they are large there is a possibility of the bun hurting themselves. The package should say how many grids are in a package. If you want to build a condo or a pen you need to figure out how big you want. And then from there you can figure out how many boxes you would need. (Divide the width/length of the cube into how long/wide you want to make your rabitat. Sketching out your idea, also, really helps.) It depends o what type of living situation that your bun came from to determine what is best for them. Some buns are not fond of condos while others do not mind it. So it all depends.

They vary by brand, that one looks like it would be 16. A cube has 6 side, but on the storage cube one side is open, so 5 grids for the first cube. Since the second cube shares a side with the first cube, it only has 4 grids. Again the third cube shares a side with the first cube, so 4 more grids. Finally the forth cube shares sides with both the second and the third cube, so it only has 3 grids.

5+4+4+3=16

How many grids you need varies a lot depending on things like are you going to use them for the floors or just the wall? Do you need a top? As well as size.

If you are going really minimal, by using grids only for sides and not flooring or a top, and you make it 2 wide by 3 long by 3 high you need 30 grids. So, 2 boxes as a bare minimum.

Yes, you can use them for bunny proofing. They can be put together, then taken apart and totally reconfigured over and over. They are the handiest things ever.

The above would be the min. needed for a single rabbit. Each grid is 14″ and the min. recommended cage size for a single rabbit is 4’X2′ or 8sq ft. 3X2 grids comes out to about 8.1 sq ft.