The Rear Derailleur Cage Is Rubbing against My Tacx Neo 2T

When installing the cassette on my Neo 2T trainer, I have to use the additional spacer to prevent the rear derailleur cage from rubbing against a rotating part of the trainer when the chain is around the innermost cog. Inserting the additional spacer moves the entire cassette outward, and alters the chainline. Consequently, the front derailleur no longer trims properly. For example, when the chain is running between the middle of the cassette and the inner ring of the crankset, it rubs the outer cage plate of the front derailleur. I could adjust the front derailleur to compensate, but then it would be out of adjustment when I mount the rear wheel to ride outdoors.

The other day I described the situation while chatting with someone in support. Eventually they asked me to send pictures. I didn't have time, and I'm really not inclined to do so since this is a problem about which Tacex is well aware. It's the reason they ship the Neo with an extra spacer!

The problem with the Neo necessitates one derailleur set up for indoors, and another for outdoors. That's something I'd really rather not be bothered with. It would be nice if Di2 provided a way to save multiple configurations. Then I could simply switch between configurations as needed.

Recently I brought my bike along while traveling to another state. I wanted to be able to ride indoors, but didn't want to haul the Neo. Consequently, I ended up renting a trainer once I reached my destination. I didn't specify a particular brand, and they sent me a Wahoo KICKR. The KICKR does not have the problem that the Neo does. The chain line remains true, and there is no inordinate rubbing. I didn't realize how much that annoyed me until I no longer had to tolerate it.

The Tacx Neo is a great trainer, about which I really have only one complaint. I was hoping that a couple of years in, the folks at Tacx might have come up with another solution. Short of redesigning the trainer, I really can't imagine anything else that would work. If anyone has any ideas, I'm open to suggestions.