REL Strata III Setup - Help

I have a STRATA III and don't quite understand the directions, in particular the mode selector. I am running a 2 channel system with Dali MS5 speakers. It is not clear to me whether the mode should be LFE or Line. Or if it should be "180 DEG" or "0" as far as phase goes. Reference page 5 of the instructions where they "explain" this. Just wondering if any of you have advice in this area? Thanks for your help.
LFE is low frequency usually from a AVR sub output. Use this if you use the crossover in your AVR. Line is a full range signal from your line out. Use this if you are not using a crossover, and adjust the crossover setting on your sub to blend the best with your main speakers.

"180 DEG" or "0" as far as phase goes" Set this where the bass and PRAT are best at the listening position.

Hope this helps-
You stated that it is a 2 channel system, the best method is to use the neutrik connection and use the "High" level, if you use only the neutrik connection then the LFE or line setting is not used ,it is only used for the "Low" level, but the phase setting is still in use , see Srwooten's answer. Hope this helps
Fatman is right.
As far as phase is concerned, I would settle for the position where the bass is loudest and best defined. If your sub is behind the right or left of a main speaker it is generally zero, but not always. You will have to use your ears. Vice versa if you placed the sub near your listening position, but again, " it ain't necessarily so ". Depends heavily on speaker placement and your room.
Thanks for the response. I am using the nuetrik connection in 2 channel only and the sub is in between the 2 speakers. Based on the answers above I should not use LFE for 2 channel and the rest of the settings can be used based on how it sounds in my room.

Srwooten - what is PRAT?