there are others gaspedal types out there also
prijon, seaward, pedal attachment to your yakimas by kajaksport. the toe control with fixed pegs is a better way to go than just the sliders.

for homebuilt i think lee has made some hinged toeflappers for his yakimas.

the driver is the amt of toe deflection vs the line placement off the rudder axis, but not much deflection angle is efficient so no big problem.

could get fancy and attach the line to the front of the peg rack and thru the ctr of the peg and top of the toe flap to get auto adjust.

could extend line below peg axis to inc line movement.

the idea of having pegs or footrest you can brace against is most helpful.