Time to quit flogging the poodle here. Sometimes the first answer is the right answer. There's nothing for it but to discard the present dog's breakfast and start over doing it correctly. You can't polish a turd.
Don't feel bad. It's not even your work. It's of no value. The wood is substandard. Use the disassembled old stuff as patterns and cut out new. Make adjustments for single layer planking and spile and plank it correctly. There's no point in doing the planking twice. Get yourself some nice Alaskan Yellow Cedar for planking stock. It's relatively inexpensive and easy to work.
Don't feel bad. It's not even your work. It's of no value. The wood is substandard. Use the disassembled old stuff as patterns and cut out new. Make adjustments for single layer planking and spile and plank it correctly. There's no point in doing the planking twice. Get yourself some nice Alaskan Yellow Cedar for planking stock. It's relatively inexpensive and easy to work.