ᐅ BESTA IKEA Shelf Assembly – Clarifying Open Questions

Hello,

I am planning to place several Besta shelving units side by side for my DVD collection. I haven’t bought the shelves yet, but I have read the assembly instructions online and some things are unclear to me:

1. Do I need to mount the Besta units to the wall? I am planning to buy the 60x20x192cm (24x8x75 inches) shelves.
2. What are the two parts (114930) on the back for?
3. If I place multiple units side by side, can they be screwed together?
4. The online planning tool does not allow me to use the ladder with the 20cm (8 inches) deep units, only with the 40cm (16 inches) deep ones. Does anyone know why?

I would really appreciate it if someone could answer these questions – some might be a bit silly.

1. Yes, the base area carries too high a risk of being accidentally knocked over.
2. Wall mounting
3. See installation instructions, last page
4. I think it’s an error in the planner, but I’m not really sure.

...and don’t forget that the 20cm (8 inches) depth is discontinued at Ikea and is already unavailable in several house models...