Not really trying to give you any advice, or start a debate, because I know about the reccomendation to delay weaning to 6 mos (although here in the uk it tends to be more relaxed around 4 mos) but just to share my experience.
I too had a BIG BIG boy - put on 2lbs the week he was born (at 9lb!) and didn't stop. Off all the growth charts and the appetite of an ox. He never slept that great at night anyway, but at around 13 weeks started waking more and more and downing bottles like there was no tomorrow - a few times he ate 15 oz in one feed and still screamed for more. Following discussion with my HV we decided to start weaning at around 15 weeks. Within a week everything was fine, even though he still wasn't taking hardly any solids.
Sounds like your little boy is exactly the same. The way I see it you have 3 choices - try and feed him more during the day and see if this reduces the night wakings, accept this pattern of behaviour until 6 mos and live with it, or go with the flow for as long as you can, but accept that you will start weaning before 6 mos, when the going gets too rough.
You may be able to hold out as it sounds like your lo is generally quite content during the day - my lo was a complete and utter nightmare the whole time, very unsettled and literally screaming for food. To be honest - not much changes, and he's 2 now!!!!! Boys eh
- good job they love cudles!