All true.
Better yet, look at the PAC 1200 instruction manual...
View attachment 117394
Wow! The rowers seat is quite high!!!
Ultimately, the best rowing ergonomics is to have the end of the oar handles a fist width apart, and when rowing backwards the your hands should be mid chest. In this position you will have the most power with the least amount of fatigue, and will have clearance from hitting your knees when rowing(especially through rapids)
If when rowing backwards your hands end up at shoulder level or higher, you will become fatigued quickly and your power will significantly reduced.
If your hands end up below mid chest, you'll have a clearance problem and reduced power.
I have a 11' boat with 18" diameter tubes, the oarlocks are 57" apart and I have 7½' oars. With that setup, my hand were above shoulder level, so I raised the seat 2½" and now it's perfect!
I must add that it came with 7' oars, which were way too short for the design. I'm 6'2", so someone shorter would've been rowing at head level. It's seems many manufacturers are somewhat oblivious to rowing ergonomics. I've contacted a couple companies with the complaint....they seem a little perplexed on the concept.