Confused about drawers

I'd like to create a vertically stacked set of 1x2 drawers. I thought that I would need to print:
- Shell
- Insert
- 2 Drawers

But, the drawers don't fit in the insert, and in the shell alone, the top one (obviously) doesn't sit right.

What am I missing here? I feel like there's a piece I need to print that would go in between the two drawers and keep them nicely separated? Or do I just need to print 2 1x2 shells for the vertical stacking?

Thanks in advance!