My printer is a Prusa i3 mk2 with the multi material kit. It does an excellent job.
I use Fusion for design but when I notice an error in the slicer , even if it says it fixed it, I check it out in NetFab I'm still using an old version as I refuse to pay subscription prices for rarely used software.
As for the cap it printed, it is really odd and fascinating. It started at the third ring from the top and was bridged in one layer, no layer adhésion to the above layer but solid. And once I sliced it through and tried to peel it, it came right off.
Maybe Slic3r (Prusa edition) detected a hidden plane? Or just freaked out. Either way Meshmixer or NetFab can help you reduce some polygons to help speed up the prints. Just check your previews before you send the code to the printer or SD card.
Thanks again for the designs their really nice