So how many syns do you think you need for a weekend where you'd not feel deprived? Have you thought about looking at alternatives, for example lower syn curries, lower syn drinks, so you can still enjoy yourself but within reason.
There's a saying 'if you keep doing the same things you're going to get the same results' so if you want to lose weight you are going to have to make changes, all be it little ones but changes.
Have you tried having your syns on a weekly basis, for some people it works, for others it doesn't but it's worth a try.