I'm not familiar with the cup holders in the Model X, but I know the ones in the Model S are adjustable.
That not being the case with the cup holders in the Model 3, has anyone found a specific brand, model and capacity of vacuum insulated tumbler, without a handle, that fits very shuggly in the cup holders in the Model 3?
The best I have found for my Model 3 is the Contigo Byron in either the 16 or 20 ounce size, but neither fits snuggly, leading to fluid in the vessels slopping out of the sip-hole unless the opening is sealed (which makes drinking a burden).
Thanks for you help, and I'm hoping others have had more luck with this issue than I!
I know this may seem trivial to others, but the the tumbler's fit in the cup

holder allow coffee -- which is acidic! -- to slosh out of the cup and spil onto the copnsole on its way to collecting in the holder.