I originally thought that 32 players would be a good number because it's the new unofficial minimum participant number that all events should have. Considering how much work it takes to start PvP events and how many active community members we have, 16 players is not that much.
It's now clear to me that the reason for not getting those 32 players is the fact that this event requires Chess skills as well, which makes it really niche. Not many people know all the rules of chess, let alone be any good at it. Arena is probably second biggest factor.
I was thinking of ways to fix that problem for the next event, and I thought about the possibility of having 2-player teams where other player does the chess part and the other does Elements. Not the most awesome solution, but some kind of trick that like could be used to double the amount of participants. Then again if this first event is successful and fun, maybe it attracts more people next time.
I don't think that having a kind of "beta" with smaller numbers is a good idea for any event because it will take months before the next event happens. We have a lot of new events coming up and there is a limit on how many we can run at once. But now since the 32 is most likely not going to happen, it's going to be a 16-player "beta" regardless of what we decide.
My recommendation is that you start the event today with 16/16.
Btw, one option for this event is to run it continuously in some other forum section with a smaller group of "chess elite". This way you don't have to wait for rotation, but it will also make the event unofficial which means less publicity and interest.
To be honest, the very first version of the game included 16 vs 16 players on one board, every player impersonating one piece, but it quickly became obvious that a high number of the players are left out of the action (guarding a hourglass, pawns blocking pawns, etc.) throughout a match, so we had to ditch that. I'm a bit sad though, that the hype I felt at the beggining died out so fast, but I hope at least this few people will have a good playing experience and a possible next one will earn a more impassioned welcome. Though, I'm still thinking about 'tricks' you mentioned, how to involve more players in the game.
Anyway, I really hope people did not get discouraged by the needs of chess skill too, because this was the first reason behind modifying the board layout - mostly to make common chess tactics/openings useless here.
And as it was already said before:
At first glance is looks horribly complex, but when you read it over it's amazingly simple and easy enough for even a chess novice to be able to take part in.
I think most people only got scared by the wall of text called Rules, which I have no idea how to simplify more yet. But I agree with TStar here, it may be scary for first glance, but if read through a few times, I think it should become clear enough for anyone - it's much more simple in practice than in theory. I tried to make it 'chess-newb' friendly as I could, though I can't and don't really want to weed out the strategic aspect of the game, and that is all dependant on the player.
But let's see how it turns out for now, the event has started.
Edit: Oh, and about the 'other forum section': would this make Chess into something like a Forum-game, like Mafia and the others?
