Thanks for the thoughts. I used a combination of bolts and screw-in Ameristeps (round rod) this year for both climbing and for my ROS. I found them uncomfortable for the ROS after an hour or so unless I put in enough steps, close enough together to bridge two steps with each foot. All that "screwing around" while perched on my top step became frustrating and sometimes painful on my feet. That convinced me to try a strap-on ROS. I'm hoping that it will be quicker, easier, and more comfy, at the acknowledged expense of additional bulk.
The bullman steps are definitely easier, as it is just a strap and go. I found that i really had to double up the steps to not have as much slipping from side pressure. So mine were set up kind of like a Y formation on the tree, that is why I thought about using the bolts as a platform. I have been considering the Squirrel Steps, but the $$ makes it hard to pull the trigger. I guess buy once, cry once!!