There basically are two designs included in this suite. One has separate legs and the other design does not. One is a two wall version not intended to be printed in spiral vase mode.
All the others are intended to be printed as a corkscrew, vase mode, single wall layer print.
With the separate leg version, there is a built in support in the bottom due to the leg separation at 25% of the first layers. I did not use any additional support. Just slowed down some and .2mm layers using PLA.
You can also print the single wall designs with 2 outer layers turning off corkscrew/vase, single wall mode and increasing the wall layers. Leave top layers off (0). This will yield a stronger piece that is more likely to be water tight.