today i changed from 45 degrees bb rows to pendlay rows and it was very hard. i chose too much weight for the first working set and had to go down. i think i will even go down more. your post motivates me to stay at pendlay rows, KPj!
Just keep it light and high reps until you feel good about them. It takes a few sessions (at least).
I just ramped up in sets of 8 starting with a light weight until it felt messy or I couldn't get the reps. One day it will just feel great.
Also, when you get to a heavy weight (relatively speaking), it always feels messier than it is. I would recommend filming yourself, to allow you to connect "feel" with what it actually looks like.