I tried out ecm vs AP. And you guys are right they work much better for the cost

So, as a relatively new player, I've been drawn to this list and have been running variations. I am really curious about the last, squadron less list. I'm always worried about running without some sort of fighter screen, so my question is this: how to Mk II B's and a Neb B deal with a Rhymer Ball or a list with a substantial fighter force with little anti-squadron protection?