155 and 50% should be sufficient as I did it with 111 and 50% - it didn’t really take that long but I can’t tell the exact numbers because - again - I kept trying sporadically, not all days, not all sigils.
The winning team was 2x Warrior/2x Indrajit (I also tried with 2x Warrior/Mage/Indrajit a few times but didn’t like the way Mage tended leaving whole board for enemies to use, so - sorry, girl, you’re not on my team).
The basic strategy is, as you say, buffing Warriors (especially top one) enough to take them down with skulls rather easily; Indrajit is not a reliable source of damage (magic stat is too low), it’s just for small pokes and hopefully getting rid of weak stragglers.
Read a few posts from here down for some more detailed explanations.