Awesome post MR

I also had loads of milk and flat nipples and a very efficient feeder! I think the speed of your milk flow may be distressing him...so if there is loads of gulping then maybe it's fast. Expressing a bit when you first get that let down should help, so it doesn't shoot down his throat too much.

I also used block feeding to help which is feeding from the same breast in any two hour period before changing sides. It helps if you have lots of milk and a baby who likes to suck a lot... They can then use the breast for comfort without being drowned in milk. It also means they get the rich creamy hindmilk.

Good luck!