Is thunder a good match fow hornet? cuz i play both weapons, i dont wanna suck on any of them

I have m2 isida, m0 thunder, m0 viking and m0 hornet, i have 3772 crystals and im thinking of getting 10000 till the discount on may and buy a m3 isida, i also want thunder, but im not sure about body, should i ugrade thunder first and then body, or first of all body and then thunder, and which body would be best for me? horner or viking?