As time passes, I think the first prints will have a decent chance of maintaining some degree of value as long as Bastian keeps doing what he's doing. Do I predict the success of a TMNT franchise, with a Saturday cartoon, action figures, etc., probably not. So I would expect prices to come down some, once the hysteria subsides.
But, it's the future of the comic that Bastian is worried about, so hopefully he can get this book to the masses with the collected volume... and avoid underestimating demand and short printing that. I think that his publisher is aware in the demand spike and working on some ideas.
You're rolling the dice, paying some of the prices that I've seen realized on eBay for the original first issue. If Julio has deep pockets, he could keep those closing prices pretty high though.