so now its done. My Norse team played their first three friendly games to get ready for the next season

Its the first time i ever play the norse, so some advice would really be nice. i usually planned to give all of my 4 blitzers piling on first but now i m not sure if i could live without guard. On the other hand the frenzy trait doesnt make guard really good and the combo of guard and piling on isnt good either. Do you think its possible to give them piling on and then mighty blow and stay without guard?
So how to develop those for nice berserkers?
Thanks for every advice.