Great idea with the cotter pins but I would remove the lock washers and replace them with flat washers. You can grind them to fit. Grinding the lock washers compromised their integrity. If they crack and most likely will, they’ll fall out and now your mount will be loose.
I will replace the lock washers with flat washers. I did not use the same ones from the pictures above, but I did grind the new ones a little less. Still, I'll get them changed out tomorrow. Thanks.
