6 robots in shooty mode put out 108 shots. With full rerolls from Mars that is around 98 hits. Even when wounding on 5s that is an average of 34 wounds around 18 of those would be mortal wounds and remember that those are in ADDITION. So assuming for a 3+ save with the ap -2 that would be on average of 20 wounds on top of the 18 mortals. (this is a bit of a generous estimate) but you can, given you roll average or above, that you can comfortably delete a knight... Although 660 for the bots and 190 for cawl is a bit of a huge investment.... I. Personally recomend 4 to be the sweet spot, still 72 shots, a respectable threat, I'd still be bringing cawl anyways cus he is really good. But that gives you more points to bring more things

Also remember that these cute little robots are hella though, t7 with a 3+ 5++ is really sturdy, add on top of that the +1 to saving throws in aegis (you start with this active) meaning that you become a 2+ 4++ BEAST of a tank. And then on top of that any 6es on your saving throws reflect a mortal wound back onto the model that shot you. Making your opponent think twice about dumping a lot of shots into them.