How to pace breastfeeding baby?

Hi all, so I am EBF my baby. Things had a rocky start but now they’re so much better. However, now he spits up like a lot. Not after every nursing but when he does it’s like projectile spit up. Is it possible he’s eating too much or too fast or a combo of both? And does anyone have experience with that? After our rocky start I don’t want to ruin it with this since he finally got to where he could latch correctly. Sometimes he could nurse for 20 minutes and be done and sometimes it’s a hour. It just doesn’t make sense. Anyone else have any experiences to share?