I would think 3 pieces for the cushions would be better. If you did 5, the small corner pieces would probably be perpetually displaced. Are you considering back cushions? I don't think you need to cover the lip, but a thick enough back cushion would mitigate any head-banging risk, assuming the seat is deep enough for one.

I also think 3 pieces. Whatever you design, consider adding velcro on the wood and cushion bottoms to help ensure they stay in place. Also - try different depths of pillows before you decide on back cushions. It doesn't appear that you have the bench depth to use them (but that might just be the angle of the photo).

Assuming this will be used with a table, I don’t think a back cushion is needed. If you’re worried about folks bumping their beans on that ledge, you should probably just remove it altogether. As for the seat bottom cushions, you could have three made in this configuration: one straight and two “J”-shaped to cover each corner and end. Make sure to add heavy-duty Velcro or snaps to the bottoms so they stay put!

Thank you for all your comments! I like the idea of using 3 pieces, one rectangle and two J-shaped corner pieces. The bench depth is only about an inch, so I can see where back cushions may not work. I may throw some toss pillows on there to give some back support and help folks from leaning back into the lip. Great idea on the Velcro tabs too. Thanks!

I would remove the piece at the top that will make sitting there very awakward not to mention that that kind of seating is a PITA all the time.

Three pieces, reversible so you can swap left and right to even the wear. Remove the ledge to avoid head banging.

Reversible cushions is a great idea, thanks for the tip. I'll give some more thought on removing the ledge too. Thanks!