Something Ive always wanted to do.
I think its very doable!! No way in hell I would do it solo boat though. Not that far out. Team of boats and you would be laughing!
Although, I would pick the shortest route for fuel preservation, which to me it looks 140km from Port Clinton?? 140km out is a typical trip from Gladstone to the more productive reefs (Moresby/habberfield etc..).
PM me when you are planning a trip.