well.. I cant predict how EFD value will change, thats pretty much in your hands
30k efd for 3 days is ~100 ped a day though going by the last efd auctions wich is moreless what an average LA can bring in. Maybe you could add some options to buy part in the space? as in 1/10 views or something? That might enable smaller buisnesses as shop owners and such to buy their little adspace.
You say you intention is to make
EF better for everyone, so why not make this available for other people than me, neverdie, deathifier and some other privileged warants members? Should the interest be too great you can always increase price gradually later, or implement quotas.
Although I realise these money don't go directly to you since you do the EFD thing I'm already donating $100 a month to this forum. I don't see me paying 200$ more a month for some adspace.