[How do I launch cartridges in MAME?]

Yep, that's me.
EmuCon is now discontinued though. I'm only focusing in Emu Loader now.
I hope it's ok me replying posts here to help fellow emu gamers.

[How do I launch cartridges in MAME?]

To run a Watara SuperVision, you need the gamename.zip file for the game and, of course, a MAME machine set. There a 5 machine sets to choose from.

mame.exe svision -cart1 gamename

svision is the machine name.

-cart1 is safer than just "-cart", and it works for all machines, even if there is only one cartridge slot.

If you open mamedir\hash\svision.xml, look for a supported="no" entry. All games with this tag are not yet supported by MAME, even if listed in the .xml file.

Same rules apply to game.com (hash\gamecom.xml).