[Baalz]

A couple of their national heroes can cast the (level 4?) spell and I was referring to the national ones (don't remember the name) who are summoned 3 to a casting so you don't need too many casters. Also, I think they just require one path in air, and with solid air site searching it shouldn't be too hard to line up 50 gems for a single empowering. Over 10 turns a single caster can mass 30 lighting throwers who will decimate most non-lighting immune armies (particularly in the dark with no effective counter fire and easy access to wind guide).

I guess you're right that it's not "easy" access, but easy enough.