ZoomText installs 2 drivers in XP "Ai2sXP" and "NetworkX", thinapp doesnt support drivers and even if the application launches, it will not have full funtionality, so unless you are very sure you can use the application without these drivers coming into play, I wouldnt recommend thinapp for ZoomText.
Maybe others have workaround...
Have you actually gotten Zoomtext to work with View? My screen goes to garbage when I try to run it on a thin client. It's like it can't keep up with the screen refresh or something.
I realize this is a very old thread, but if you are still interested in accessibility, I invite you to check out SuperNova Enterprise from Dolphin in the UK. Support for VMWare Horizon was recently introduced in the 18.02 update.
More information, including a free 30 day trial, system requirements and MSI redistributables available here:
Your feedback would be very welcome.