You probably won't be able to gather 500 skeletons in 2 weeks.
In a tournament with 127 players, I saw 530 skeletons. Galtran, level 11, and 2-3 Necromancers of a lower level tried their best. It's simply impossible to gather all the artifacts for Necropolis in time; a well-leveled Galtran will arrive earlier, even on XL difficulty.
Sorry for the off-topic, I wanted to talk about the sixth game. Without a doubt, I liked the game. Since the third game and Age of Wonders, I've been indifferent to all strategy games. This one caught my attention. If Ubisoft supports it, I'll try to organize large tournaments, like in the third game. If not, we'll play in our city; about 10 people have already become familiar with the game, and there will be more when the game is released.
It's a pity that the beta expires today. I hope the demo will remain. Otherwise, I'm waiting for the official release.