LoS is one point at which my friend and I play a house rule actually.
Rules as written:
Own units block LoS, but models of the same unit don't, so two Skinks of the same unit don't block each other while they do block Razordons behind them.
BUT if you can point a laser pointer and hit ANY part of both (shooting and the unit you shoot at) models with it at the same time, then there is LoS.
That basically says: You can almost always hit. just measure line of sight to the tip of an enemy banner or something stupid like that.
Rules as I play it: I take the base and imagine a cylinder that is as high as the model is, or a bit higher, and consider that solid.
In fact: I am OK with hiding a slightly larger (one base size bigger) model behind such a screen, such as a Lord-Relictor behind Liberators or a Starpriest behind Skinks, a Necromancer behind Skeletons or a Megaboss behind some Ardboys (although that last one is a stretch as there are two base sized between those).
I also don't count bases. I don't want to punish people for putting their heroes on large rocks (Abhorrant Ghoul King for example, or my friend's awesome Megaboos who is standing on a huge rock).
So if you want to check if LoS is there between models, you check if the models are standing in base to base contact. And don't fight about a millimeter or two. Shooting is strong so when in doubt, say it is no LoS
It is a bit of a common sense approach so you have to talk about it with your opponent so everybody is clear about it.
I am almost sure you could even make a general rule based on base sizes what can hide behind what. And that's what GW should do. LoS rules in AoS are a mess.
So if I fail my priest rerolls. I cant use the slann’s commandability?
