I’m using a MIDI pedalboard to toggle parameters and channels in S-Gear, but I’m getting a significant volume jump when switching from clean to overdrive.
On physical amps, I'm used to using a dedicated post-preamp volume or channel level control to equalize output levels. What is the recommended way to balance channel volumes in S-Gear without resorting to separate presets? Is there an internal channel level control or trim I should be tweaking, or is preset switching the standard workaround?
Thanks!

In this situation I'd suggest using preset switching, it's pretty much an instant switch.
Unless you can control your CC ranges with your controller, that would be the other way perhaps.
Using the CC to send a specific amount of CC change, and of course map it to the amps output.