For Alliance-8 it's quite an easy job - pick Tortoise, big gun & full HE. Aim for cuppolas or side of the turrents, sometimes lower front plate. It's easiest to hit crew members. Take a look also at wotinspector.com to understand where crew sits and internal modules are. I did it with Tortoise with 1st serious try, was 2 crits short from honour score.
Now I'm stuggling with same mission but for Coalition. For now Prog 66 with HE works most consistent. In first try was 3 crits short from completing . Just started my next attempt and in first game got 5 crits, pls keep fingers crossed