Ok, I got it: maybe this will be clear, sorry I was scatterbrained last night at 1AM had to get to sleep for work.

The outer rail:

slider
which hooks into the rail (can take this off)

slider which hooks into the rail which hooks into the metal piece that includes the sliding/tilt mechanism (or take this entire unit off)

So for you del sol swap guys did you end up swapping your tilt/recline mechanism too or is this not a part of the rail swap?

thanks