Usually a w/d/w rig has dry sound in the center speaker and the only process applied to it are typically in_line "fx" like compression/wah/eq.
All time domain fx, such as chorus/flanger/phaser (yes, these are TD, even though phaser is made with filters but many do with micro_delays), pitch/delay/verb are in the L/R speakers.
The point here though is about dry sound being always present in the MIDI Virtual racks by design, so if you use a MVRack preset in a w/d/w setup you'll end up with dry sound on all 3 speakers. He needs to remove the dry part from the preset. Problem is that these structures are extremely complex in their routings and require skilled Vsig work. The reason for the dry to be in these presets is that the A/D_D/A converters of the H-series are so good one won't notice the difference with the true dry sound. In addition to this, since there are often "in line" fx like the 3 mentioned above, removing the dry sound may impact on the whole preset structure. An attempt could be trying to mute the very end of the dry sound in the preset as this would remove it from the final mix of the preset, still keeping the time domain effects fed by eq/wah/compression, where present.
The philosophy of MVRacks presets is to have highly powerful programmable and flexable structures requiring no preset change by means of internally stored tweaks (10!). A single CC message with values 1>10 would simply recall each tweak, provided a "modern" MIDI pedalboard is eing used. As they are, we recommend them for typical stereo use. W/d/w setups will require a totally different programming approach, leading to massive dismantling of these structures.
We may include some new versions for d/w/d setups in the future.
all the best