help me consolidate DS nighttime sleep don't know where to start

[Liveinthepresent]

DS is 16 weeks.
He is getting the hang of settling to sleep by himself - naps plenty. ( too much) during the day.
On a good night he will sleep from approx midnight to 5 and then after a very short feed back down until 8.
He is getting between 12-14 hours sleep a day.
He is showing no signs of extending much beyond this 5 hour stint yet.

This is all ok and I am feeling like I can get enough rest like this - but the thing I need to tackle is getting some of his sleep to happen during the evening and promote a proper bedtime ideally 8 pm- at the moment I feel like he is probably ready for this but the current pattern is just reinforcing a fairly short night - made up for by napping loads in the day. He is awake for 2 hours from 10 pm until midnight otherwise he isn't sleepy enough.

I am reading NCSS and there are lots of good ideas in there - but I still dont know where to start - am scared that unless I think very carefully about how to do it he will start doing his 5 hours from 8-1 and then my nights will be very wakeful.
I have a 2.5 year old too so I really don't want to risk getting too knackered again as it affects how on form I am for her and DH.

Has anyone else had to deal with this ?
DD was sleeping 7-7 by this time pretty much all by herself so am at a bit of a loss.

TIA

DS1 also was sleeping 7-7 by 17 weeks and still more or less does this at 27 months. DS2 is 9 months and has only been sleeping through for 2 weeks. He was napping in the day and sleeping 7-12 then up every 2 hours after that until 6am until 7 months.

I decided to have quite a strict sleeping routine - bed at 7pm and only feed/settle him in the dark. up at 6-6.30am. Nap at around 9am and again at 1pm. I couldn't let him cry as it always woke up DS1. In the end I had to make sure he was getting enough calories during the day - 3 meals and snacks so eating every 2 hours. Plus he slept better when I stopped feeding him at during the night. This all took a long time and a lot of trial and error. He's EBF and refuses a bottle too. I was so tired as DS1 dropped his daytime nap just before DS2 was born.

I don't think we'd have had DS2 so quickly if DS1 had been as bad a sleeper!

Thanks for the reply - I can see why you chose your user name!
I am very lucky that DD still naps every day.
I am so undecided as to whether to do this - the prospect of waking every 2 hours again fills me with dread. But I think if I point tackle it he has no reason to change his pattern as he gets plenty of sleep.
My dithering continues!