Since edits are disabled on the original post, I’m posting this addendum.
You can use this tray without the tablet section attached:
This makes sense if you already have the system and still want the option of tablet use - say, for travel.
I’ve since switched to a Foothill Products “Trainer Tray” that attaches via a Garmin (or Wahoo) twist-lock mount:
If you never intend to use a tablet, the Trainer Tray would be more economical than buying the Tacx Tablet holder + phone tray, never mind less work than modifying the phone tray to fit.
I also installed the optional “out-front” mount which would let me attach a bike computer ahead of the tray. (pending purchase)
I only have one ride in with this but like it so far. It’s more practical if you already have a computer mount and plan to use your bike outdoors as well.
EDIT - many, many rides now with both the modified Tacx mount and the Trainer Tray and they’re both excellent.