View attachment 20124
Additionally the same parameter can be found on the "PWR" page, the "DYN" page and the "TREM/MIX" page of the amp block using the front panel.
Since you've balanced and set your level, all you need to do is set the maximum parameter to that level, not leave it at the default +20. So If you've adjusted your volume to -12 like I have in the attached picture, then you set the max to -12. This is far from useless, just takes a little understanding how it works to set the range properly.
IMO it's not worth adding a volume block when you already have the control right there. And this control is available on every block, not just the amp block.
If you want it to swell in then you need to adjust it via dampening. Using a volume block does not change this as the control modifier page is the same. If you don't adjust it then it will be real time as fast as you move your expression pedal.
View attachment 20125
Another option would be to also attach the envelop modifier, but that's getting a little advanced for this application.