here is a pic of my project check it out see what you think
Are you going to make a spring seat?
It will be a much more comfortable ride.
Here is how I make my spring "PIZZA" seat.
IT starts with a Ford 9N flip over tractor seat.
I drill the spot welds out on the hinge on the Ford seat and it comes right off.
I weld 1/4 inch solid round bar all around the edges.
3/16 flat bar T frame on the bottom to connect to the hinge on the frame.
I use 3 inch bee hive springs.
The hump near the front helps to keep you from sliding forward.