Some performance and various tips follow. Just a FYI, maybe you already noticed, maybe not:

As per the documentation, disabling self collision vastly improves simulation speed, especially on meshes with many polygons, wether the cloth really collides or not. Disable it for any cloth that you don't expect to crumple on itself (leave it on for a scarf, disable it for a T-shirt).

Setting Resolution to Base (disable SubD) prior importing the cloth to VWD has 2 advantages: faster sim due to less calculation, and more accurate cloth behavior. Many new clothes are so dense that they behave as they weigh a lot and are very soft, because the vertices are too close to each other and their deformations add to each other. You can add back both SubD and Smoothing Modifier, complete with collision, after sending the result of the simulation to D|S. Optimal spacing between vertices in VWD seems to be circa 3/4 inch or 2 cm.

Previous versions of the bridge automatically disabled the collider SubD, not the latest one to date. On my system the SubD applied to the collider doesn't seem to slow the simulation much. Its impact is way less than self collision or the density of the cloth.

Disabling the Floor collision leads to minor improvement in performance, just enough to justify leaving it off unless required. As with self collision, simulation slows down even if the Floor is not touched. Leaving it on is better than importing a mesh as your floor. You may have noticed that you can adjust the floor location along the Y axis, I find this very useful. It could be even better if we could set it as a "buoyancy limit" for scenes with people in water, but that would get limited use I suppose.

The Gravity parameter is not to be intended as a real world parameter (although you would lower it for Mars and increase it on Jupiter), but as a measure of the weight of every vertex on your cloth. So Jeans tissue would get higher gravity than a polyester one, but lower gravity than a carpet. If you have to simulate the Magic Carpet, turn off Gravity and use Stiffness/Rigidification to move the cloth according to its nature. Clothes with higher gravity require less Softness to hold together. Valid values seem to range between 1 and 0.0001. Could the authors confirm this range?

I'm nowhere near to full understanding and mastering VWD, but the above may be useful for anyone, so here you are :)