If I was going on your dates, I'd definitely make the effort to get to Space closing. It will be busy, but probably not as busy as the few weeks before as a lot of nights will have already had their closing parties.
If I was out there on your dates, I'd smash it for the first 3 nights then deal with the consequences in the remaining days. Mulletover @ Sankeys saturday, Space closing sunday, Cocoon closing @ Amnesia Monday. Then you've got 3 days to chill and marvel at your efforts over the previous 3 days, and there will still be enough to do if you've got enough money/energy left.