am no expert, have one child and am making it up as i go along, but i had fast let down so can give you my tips til someone more experienced comes on...
from what you say it sounds to me like you do have a fast let down. my ds used to come one and off spluttering and the milk kept coming when he came off. usually hit him in that face!
tips i was given were to press above the nipple as you feed, which apparently slows the flow down. that worked for me. or to feed him so his mouth is "above" the flow - couldn't get the hang of that one.or to express the beginning bit before feeding, so it's less fast when your ds gets it.
my ds also settled really quickly when my husband took him. so disheartening at the time. in hindsight i think it's because he doesn't smell of milk, and also prob because by that point you're likely to be a bit angst, which they can sense.
last thing, sorry, this is so long, is that i expressed and my husband gave a bottle of expressed milk at 10pm so he could share and i could get a break. that worked well for us. may be worth considering?
hope this helps. bf is hard at times. have vivid memories of trying to feed a screaming baby wondering what sort of a bonding experience it was meant to be.
ds is 6 months now and chortles at the sight of the breast.
you will get there. ((((hug))))