If you #guaranteed - you could count me in. Increasing the pot would be good. If, instead of sealing the contest (as you will no doubt be pestered to do) you put the $30.00 bucks towards the prize and added Andrew Jackson to the mix you'll get a better spread of artists interested just for the hoot and whoever needs to seal their own entry can do so themselves. 50p never broke anyone honest.
Your word upfront you'll stay open the full week and 6 days - that would definately help.