4 month sleep regression - do I bother with early bed time

[Liveinthepresent]

I keep waiting for the right time to start putting DS down at a proper time instead of when I go to bed.
The right time hasn't arrived yet and he is 18 weeks - sleep got worse again the last week or so.
At the moment his longest stretch is 2.5 hours when he first goes down - so although the theory says he will benefit from a proper nighttime - I worry I will be awake for his longest sleep and then be up every 1-2 hours for the rest of the night.
WWYD?
Anyone got any success stories - will giving him the more typical structure help or is it pointless at the moment?
I know I could go to bed at same time as him but if that's the only option I would rather stay as I am as DH and I at least have a sort of evening together after DD goes to bed currently.