The raft may not be necessary for you. On my first prints, I had issues with the ends warping (ABS). I insulated my chamber better to keep the heat in and added the raft. This resolved the issue.
The base (thin part) holds three cans together on a shelf. The center (larger) part goes on top of the previous stack. It is quite stable. I have stacked 4 rows high with no loss of stability.