Imahho, i prefer the silver los armor, other than farming the rubies, i like the ESP skill as many white sharpness weapons still bounce off the higher ranked wyverns.
And just cuz silver los is awesome, as for gunner armor, idk.
i havent been a gunner since MHF, but uhh, hmmm, I think...., erm, humph, duuh, umm, yes, i would go for blue guild guard armor. Its got normal/rapid shot up and a base def of 30, witch is pretty good, i think, not sure, i havent gunned in soo long, but you might as well use a melee wepon, like HAMMAH.so yea, i hope that helps.
Happeh Huntin!!