We will soon start a wagering contest but this time on all coins
All coins? Are you sure? What I would suggest if you open new wagering one coin each, with this I believe the prize will be huge instead of you do all coins wagering contest. I just wondering when and how much prize are you going to put in this kind of event. Because it is a wagering contest, you should do this better then a profit contest
Why not? The amount of the prize is not depending on how many coins count towards the contest. I believe the site has its own limit of fund for promo, so lets say the limit is 1btc then this 1btc will be the max prize. If the site needs to make contest for each coin then the 1btc will be spitted. As it is a new site, owner need to be so effective in doing promotions.