Before we get to SG CH 5 Full, we will have the next WIAB Beta and Full, as well as the SG CH 5 Beta.
I think we could get two revs of the CH 5 Full, the initial CH 5 Full and then last - the Season 1 Steam release (with whatever polish Ocean wants to add ahead of his Steam introduction).
I think the September time frame is reasonable given all the work he will do to get to SG Ch 5 Full.
I'd love it if it was faster than this, but not at the expense of the quality of the story and presentation.
Cheers!