Sorry, yes. i only addressed part of the problem.
I would use the emoncms “fetch” api
https://myserver.com/feed/fetch.json?ids=1,2,3&apikey=abc123
this would return the current values for feedids 1, 2 & 3 as a list of numerical data eg
[123.45, 45.678, 99.9]
Where I was going with the “oneday in emonhub” was that there will be an interfacer that “fetches” data from emoncms as above and that data can be routed to any other interfacer target eg publish it to mqtt or transmit it over RFM for a emonGLCD or indeed transmit it over UDP (or to OWL) if the interfacer is there.
For now you could write a small pythn script that fetches the data from emoncms via an api call and transmits over UDP in the format you need. I say Python because that’s what I tend to do these little script in so that they can be reused in emonhub interfacers. But you can use your language of choice.
Please post back here if you do this so that I may use it when I come to implement something in emonhub.