from my maths this is what I came up with as best rebels and imperials.

MC 75 Armoured + Sato + EL + HIE + FCT + XX-9 + CF + Opening Salvo, dice = 19 dmg

attacking front of enemy 75 + strategically placed MC75 aspiration shields and as 1 front and 5 right side, 1 left side and 6 rear. trigger HIE first to strip front and left side and - 1 on right side. both crits are projector mis for remaining shields to bring the total damage count to 32.

ISD KUAT +EL + HIE + FCT + CF + Open salvos + 4 stack Devastator for a dice total = 28 dmg

attacking MC75 Aspiration front with 1 front & both sides, + 6 rear shields, HIE 3 + projector mis for the rear 6 for a total damage count of 37