Slow follow nipples

Hey mom's I'm looking for an actual good slow flow nipple. My poor little man has been having it rough lately with bottles. He's a week and 2 days and has drinking issues already because he had a tongue tie and the cut it so now he's basically learning to suck. They had us hold him in a football hold to stimulate he was still on the breast with a cheap Enfamil nipple but we can't always do a football hold when out and about. So today I've tried doing the craddle hold and he threw up excessive amount after because it was going too fast. Avent doesn't work I've already tried, and I've been using the Dr brown stage 1 now but thinking about maybe trying the preemie? Do you know if this is an actual slower nipple? Or another one? I need it to stay slow and not just start out slow and then after a couple feeds it gets faster.