What is the best practice for handling Universes/channels with the Sandevices E682(or any controller I suppose)? I am using 8 strands of 100 pixels to make a 16x50pixel megatree. I am also using an additional strands of 50 for a tree topper. My initial thought was to use 9 universes total with 100 pixels(300 channels) on each universe except for the 9th universe which would just use 50 pixels(150 channels) but it looks like I can only use 7 universes with multicast. What do most people do in this situation? Use unicast instead?

Below is what I initially configured and then realized I couldn't have 9 universes using multicast.

Also a question specific to the E682...the E682 documentation says to use 510 channels per universe for RGB pixels but other sources have said to always use 512 channels if possible. Which is the better practice here?