The two issues, fast letdown and oversupply are often lumped together as they can have similar symptoms however there is a slight difference in approach if you just have fast letdown to if you have too much milk.
If letdown is tricky to manage,
increasing frequency of feeding can help (like you said, during the day it's more manageable) as milk volume doesn't build up as much and baby can cope better, chokes less and pulls back less. However if you are actually producing too much milk you MAY need to
reduce the frequency and duration of feeds. (This is not usually advisable with very young babies without consulting a Lactation Consultant) So two opposite approaches to something often seen as one problem.
Sounds like you are already doing good things with the reclined feeding. This info might help, although good to talk through it with a breastfeeding counsellor/peer supporter/Lactation consultant in order not to feel too overwhelmed
Too Much Milk and Oversupply - La Leche League GB
My thoughts are that if baby is doing longish stretches and seems satisfied by feeds then you probably don't have a problematically high milk supply as he is still able to access hight fat milk and he doesn't just get full of watery milk. Sounds like maybe forceful letdown is the main culprit. In which case it may be that expressing off small amounts prior to night feeds, or letting down in to a towel, so that he is more comfortable and taking in less air would work for you. As long as you don't express more than the initial letdown, it shouldn't cause increased supply. As baby grows he'll manage better with it, and as you reach growth spurts, if you do have a slight over supply these growth spurts should help, as his appetite catches up with production.
The key with both approaches is to ensure he is definitely feeding effectively. If all he's doing is drinking letdown but not actively sucking, he wont be getting what he needs (and he'll probably take more air of not latched well). Do you have any face to face support?