Okay, I can almost certainly say I will be there at Saturday show, barring some unforeseen circumstances. There's the matter of getting the tickets, but I hope it'll work out. Gonna try and grab them on a presale tomorrow.
Also, I don't know if this information is available anywhere, but I e-mailed Arjen regarding the possible differences between two shows and got a direct response from him (I swear, he's such a nice and great guy) that
SLIGHT SPOILERS AHEAD. No spoilers for any songs in the setlist though.
Direct quote from Arjen: "The plan is that it will be the same set list. But it’s always possible that certain singers will be changed. I hope not though."