Surely Hornet m2!!! I had both hornet m2 is fast and have a protection same about Viking m1... so get hornet m2

I want to get hull kit m2 without buying crystals right on warrant officer 5. how I can do this well? please help me... you can help me by saying which combo I must use In which maps and which battle mode to get most of crystals.

what is best combo for me? I mean m0!!! I like both attacking and defending and I play in all types of maps