So, I've left it running all the night and it's pushing things like a pro to my MQTT broker.
Bonus points:I've finally migrated my dashboard to WebSockets, instead of long-polling. I can't finish to press a button that the UI is updated. Brilliant! I've finally rewritten my own VeraBridge in C#, so no polling and less CPU usage on my Vera I'll probably port more things to my C# app, at this point, since I now have sub-second updates of variables I modified other parts where I was calling http endpoints from my Vera, to push UDP datagrams.
I still must find some time to fully test openLuup's MQTT broker, but @akbooer you already gave me a lot of inspiration, as always. Thanks!