Train some AMF and beat it to death with a MoD.
Well, in that case drop the Tulks for a NSC. ;) And the MoD? Sure you bypass the PL/TSA combo, but you hititng the mages natural HP with thier massive AC. And no double damage as no AS.
Somehow fit a GA into the equation? It seems feasible since your RoS is dedicated solely to SS. If it's a familiar, then it will die quick to GA due to its massive damage and due to your DM to fizzle any AS.
That's why the front minion trains DM. ;) To eat GA.
Is the reason for RoS specifically DM resistance? It seems like a lot of this tattoo is being wasted.
It's to give you near immunity through AC.
Anyway the simple answer is AMF. You don't mention Decay in the minion one description so I don't know how big you intend to train it but AMF will reduce its damage quite a bit and retaliate against the SG minion as well possibly killing it before even the PL minion dies.
Minion 1 doesn't train Decay, so it can't be killed by AMF backlash.