Update 9/17/2018: New, (no holes) version was repaired in NetFabb. Looks like the original model left some tiny holes around the base flanges.

I modded Simplemaan's (https://www.thingiverse.com/simplemaan/about) painting support triangle to have a teardrop-shaped opening on the sides. This allows the model to print OK with no support, and perfectly with Cura's "touching buildplate" support.

Prints in about 42 minutes on my Monoprice MP Delta Mini using 0.2mm layer height and 150mm/sec move and print speeds. I included a photo of the original and the modded version for comparison.

The Google Sketchup file with my mods to the original STL are included in case you would like to make other changes (and know Sketchup :) ).

Monoprice MP Delta Mini

No

0.2 is fine

doesn't matter

Use Cura's "touching buildplate" support option to get a clean slot under the 3rd side. This allows the triangles to nestle up closer to each other (but isn't really a big issue - try printing one with no support).

most useful if you print at least three: I'd recommend having 6 or so on hand.

I pulled the original STL into Google Sketchup (it's what I know) and spent some time cleaning out the extra lines from the STL format's handling of a flat surface with curved edges.

I then drew in some guidelines by finding the midpoint of the sides to use as the height to begin the taper. Extruded away the circumscribed area on each side and that's it.