A freerace/slalom fin review with focus on the typical one board and fin quiver. If you are into fins please feel free to contribute on the topic:
boardtests.com/2015/10/black-project-fins-type-r-review/
boardtests.com/2014/07/windsurfing-fins-how-do-i-choose-the-right-fin-quiver/

I have been using BP fins for a couple of years and can relate to that review.
the main thing about them is that you use a smaller fin for same upwind and secure feeling.
which means you get to go faster without the fin letting go when you are cranking back upwind.
a few days ago overpowered on my old 5.8 in an Easterly at Shallow Inlet the downhaul pulley broke and left only the line wrap holding any downhaul. (lost about 3 inches.
Felt it go but was committed against the bank, waited for the fin to let go. but No it held.

Off topic: Love that picture, great crop really captures the sensation of hooting along.

Thanks for the review. Did you use the same size sails for the posted speeds with the 35,40 and 45? I own a few Type R's myself and have to agree that they are great fins. Very well made and a good allround design.