So more of a print queue that has an hour buffer between each file printed? Otherwise, you would have to trust your print time estimates and schedule by time stamp. I haven't seen a plugin that does either of those options but have seen discussion of print queues on the issue tracker of OctoPrint before. Might be something fairly easy to program if you did something like a sub-folder just for a print queue. Upload the files you want to be in queue and start the first one. Once it completes, delete the completed one, wait configured amount of time and then start the next, repeat.