Here is a gig file that adapts an x-fader scriptlet created by @David-san to crossfade the volume of a dry signal with a signal sent to the reverb plugin.
A controller can be assigned to the Blend knob to control the fade that way, if you wish–or, just manually adjust the Blend knob and the dB levels should be equal. (thanks again @David-san for doing all the hard work with the calculations)
Blend_verb.gig (121.9 KB)