If you're using your EtherDongle with pixelnet firmware...
if you're starting with channel 1, then number them 1-1512
the software sees dmx universes, so to talk to the E1.31, you'll need at least the first 3 "DMX universes" setup setup in your software
as far as the hardware, the EtherDongle does the rest for you
E1.31 allows DMX universes to be sent over the computer network connection to a E1.31 device.
the EtherDongle setup with pixelnet firmware listens on the computer network for 32 separate DMX universes and bundles them up into it's 4 pixelnet universes.
the hardware does all the protocol switching for you.
to go off of one hub, you just need to make sure all your channels for that hub fit on one block of 4096 channels. (or 1 pixelnet universe)
so, if you have a lower count of channel for your show, keeping them under 4096 would make sure that they work.
back to the software, I believe you setup the "DMX" universes in LOR for it to talk to E1.31 so, technically, you really only need to setup DMX universes until you get above your channel count of your show.
IP Address Universe Last Channel
239.255.0.1 1 512
239.255.0.2 2 512
239.255.0.3 3 512
239.255.0.4 4 512
setting up 4 "DMX" universes will get you your 1512 channels for your megatree, plus give you at least 516 more channels for your other stuff.
(to set up all 8 universes)
239.255.0.1 1 512
239.255.0.2 2 512
239.255.0.3 3 512
239.255.0.4 4 512
239.255.0.5 5 512
239.255.0.6 6 512
239.255.0.7 7 512
239.255.0.8 8 512