013 houses 3000 people, so there will be roughly 6000 tickets available. Ultimately, this is about the same amount of people as the Theater Equation, since that show was 4*1500 seats. I think it is worth to note that quite a bit of the singers are from popular bands (for their genre) and metal concerts in 013 typically sell very well (I have seen many sold out shows there). Tickets are also way cheaper on average than for TE. But honestly, I don't know how this will sell, Dutch folks don't know Arjen Lucassen very well, even those who are into all the artists he frequently has as guests. But keep in mind 013 is fairly close for Belgian/German people as well.
I know that from Amsterdam/Rotterdam, travelling to 013 takes about 2/1,5 hours. And there are international trains (from Paris, Berlin, Antwerp) that stop fairly on the route. Getting there is no problem, if you play it safe and leave early. The problem would (potentially) be going back, as Tilburg isn't a very large station (it's not a major city of ours) and I am not sure till how late the trains will go at that time (current plans might change). So that is something to keep in mind when planning.