I fluted the armrest flanges and got the parts match drilled to the side skins. Van’s says you may flute as needed, but I doubt there’s anyone out there who can get away without fluting the parts. 
I cut the step holes in the side skin. The was a pretty fun task.
This picture shows what the step looks like when installed. I’ll need to trim about 2.5 off the mounting tube so the flange lays flat against the side skin.
Here’s an interior shot the step mounting tube. Eventually the loose end will be constrained but a UHMW block with is attached the baggage rib shown below.
