I have the same setup and added 3M stair tape to the top of the platform. Much better footing control especially when wet! Also, trash the push pins and add bolts and drill out the other 2 holes for 4 bolts and it's rock solid.
I have the same set up and a little trick I figured out on the platform comfort issue. Place your heel on the platform and put the rest of your foot on the tree, and it will surprise you how much it helps