Nothing wrong with 29/30 at very light pressure for 30 mins. To be pulling 2.09 pace at 29/30 SPM for a guy your size suggests a couple of things without seeing you.
Like most who sit on the C2 first it isn't usually a lack of effort.
Mosty probably rushing the slide. See clip here about 4:50 inhttps://www.youtube.com/watch?v=oP6OR-G7AxM
Slide and hand control is how you control rate. To slow down the rate, slow down your slide forward (and prolong your recovery). To pick up the rate, move your hands away from your body faster. In a boat rushing up the slide would act as a brake on teh boat speed as it throws weight against the direction of travel and checks the boat.
For 20 spm its easy, approx 1 sec on a stroke and 2 secs on the slide. A simple exercise is try and bring the stroke rate down to 15 spm for just a minute and keep your split under 2:10. The only way you can do that is slowing waaaaay down on the slide. That should give you a feel for the control you need on the recovery. It also mean applying twice the power!
I set the C2 level at 5.5-6. Depends on damper (wind resistance level) which is a whole other saga.