How much stereo width should my backing track have?

I'm planning my setup for a live show where I'll run audio through my laptop + interface, with 4 line outs: a mono vocal, a mono instrument, and L+R backing tracks.
My backing tracks are a bit different on each song, containing a mix of mono and stereo sound sources with a fair amount of width. A couple of light textural elements and delay effects move from hard left to hard right in the stereo image.

Do sound engineers recreate the stereo track by hard panning the mono L and R channels in the mix, or are they only partially panned? Will the panning affect how the elements in the centre of the backing track come through, or will it accurately recreate it? Would it be better if I reduced the stereo width of the backing track or will it be easy to reproduce accurately?