GUITAR STRINGS AND SETTINGS ON POWERMIXER

hi guys i hope this is not a foolish question can anybody help me out there..i play a tanglewood
nw 55 semi acoustic guitar what is the best strings to suit guitar i have been using martin sp light
also my guitar is semi acoustic and i plug it into a powermixer which is a 8 channel what is the best settings to use when i plug it into the mixer ??? thanks johnny guitar !!!