FWIW I currently have a similar situation where I want to have a 10 sec volume swell at the end of a song (Brass on Make Me Smile). Dave Dore has some awesome fader racks but would require some time to learn and modify. So I built a series of bindings at the Song level (which I will soon migrate to a rack). I’m away from my rig so can’t show a screenshot but essentially it’s song state, on load, the rack I want to swell (not the racks midi in), delay of 1000 ms, gain, and a value 2 db higher than starting point. Then just copy and paste and change the delay and vol/db to a larger value, repeat until you have the length you want. Very easy to tweak, and if you go to 1DB increments and smaller increases in the delay it gets even smoother. Oddly, by about the third or fourth binding the delay times seem to be larger than what I entered, but by simply reducing the delay and trying it a few different ways I can get the length I need. Also works on song volume or master levels. I’m sure someone else has used this work around but I didn’t find anything like that in my searches here. Hope that helps!
Tom