AM+LS combo is enticing, no doubt...i've thought about that too but making it work vs Rainbow is too much hassle because they will throw everything but the kitchen sink at you unlike say, obliterator, incarnate or gemini
plus their creatures are less susceptible to the combo (burrowed and growth) so you need a lobo effect
but lobo need protection so you can either go quint+m.flayer or lobo+PA which means another 2 elements on top of
+
its just not feasible imo
and yes, decking out is the best way for unupped but you need ways to counter at most 47(+20) damage coming your way in order to do that
assuming you went gravity shield route, burrowed shriekers x8 will do 40 (at most, if all in play), EE doing another 7 and thunderbolt x4 another 20 (not per turn but still need to be considered)