I have a few ideas that might help get you there. To do what you want to do you must have some bindings at song level to loop the data back out to the same rack. See below the song level bindings. This establishes the gain slider for your chosen rack as a generator of cc#7 events.
Next you need to re-order your racks in your songs so they can be indexed. when racks are loaded in the routing page they are indexed top to bottom 1,2,3 etc … Load your racks in the same top to bottom order in every song and give them index numbers. For instance sax rack is index 1 and so on. The main idea is keep rack order continuity through all songs. In my example “test one” rack would index#1 and rack “test two” would be index#2.
Next you can make the following changes to your rack bindings you use to auto send your MIDI presets
First create a route pass through for your MIDI messages to be passed to the output of the rack to be sent to your external keyboard like below.
Next change your internal rack bindings as follows. I tried to use some of your examples below but the important binding is the one that is circled. The target has now been changed to “Rack by Index” instead of just “Rack” so that it can pass initial values to the rack gain slider at song level and subsequently to the external midi out device as shown in figure 3. When using the "Rack target you can only address the internal output gain slider.
This approach should get you where you want to go. This keeps your rack initial bindings intact you’ve already made and establishes the link to your song level gain slider that can be still be set with rack load bindings from within the rack. Hope it works out.