I also have a DIY version, made some years ago, but without the silicone insert nor the wire tray. Maybe that's why I had a hard time using it [Poor cooking skills didn't help, either]. The Omnia oven is just a modernized version of the Israeli "Wonder Pot". It was (and still is) popular among the very religious people to satisfy religious dietary laws.
Nice job! I couldn't believe how much they jumped up in price lately... this may be the much more cost effective option. Thanks for sharing the knowledge!