Waxed paper works better than painter's tape.

Last night, I attached the blocking that will support the sides of the forward thwart. I used the same procedure as I did for the rear thwart, with one exception: This time, I taped waxed paper to the ends of the seat in order to keep from gluing the seat down just yet. Last time, I used the blue painter's tape. 

Waxed paper works much, much better.

2 bar clamps hold the level to the plywood, keeping it straight; 4 bar clamps hold the plywood to the center support; four 4-1/2" deep C clamps hold the 2 pieces of blocking in place against the underside of the seat & the sides of the hull; 2 bar clamps reversed as spreader bars push the blocking against the sides of the hull.

The waxed paper made it MUCH easier to remove the seat once the epoxy had cured, and left no mess to clean up or sand off.

Due to the variety of angled lines inside the boat, the seat blocking appears to angle downward. However, I checked, and they are indeed parallel to the keel.

Angle measurement on the rear thwart.

Angle measurement at the aft end of the keel.

Angle measurement at midship on the keel.

Angle measurement on the center support for the front seat...

...and finally, the angle measurement on the forward seat blocking. That's consistent enough for me.

Here's the topside view of the forward chine that I had to add more material to 2 years ago. (I can't believe it has been that long ago!)

Next, before I begin encapsulating the inside of the hull, I plan to add false battens to the outermost sections of the floor, just to keep from standing directly on the plywood.