But that's what you're offering in a best-case scenario situation $1000 per episode / 120 panels = $8.3 per panel. If I take the lowest you offer for an episode it's even worse (500/120=$4.1)
perhaps some would be OK drawing a panel for that little money, but from what you say there might be a lot of back and forth between you and the artists, which doesn't sound worth that money. Do you have a script with clear descriptions of what you want your artist to draw? That might ease some of the worries people might have.