NOOB - Do I need to worry about universe when using a PiHat and E1.31

[clocey]

I started playing last year and I have forgotten too much. 
I am not using anu light controllers per say I am only using RPI's with output 18 & 19 and the E1.31 PWM output.  If I recall properly the universe in xlights does not mean anything with the E1.31 configuration.  If this is the case what do I do with it. 
I plan on on having no more than 860 pixels per output so I know the little pi's can handle it
So EXACTLY what do I do with the universes?? leave them at 512 or do I use the # of pixels per channel I am using?

[n8huntsman]

Are you talking about in the setup tab of xlights?  I've always left these at 510 (or 512, doesnt really matter as long as it is equal to or greater than your (pixels x 3) it will work.  Whether these unused channels contribute to performance issues or not, Im not sure.
With as many channels as your talking though, youre most likely going to be using all of them so it's probably a moot point.
In my case, I have some outputs that have, say, 50 pixels.  That means Im only using 150 channels but in the software I allocate 510.