Welcome to the club! I was also using a vertical mouse before switching to the UHK. I purchased both the trackball and trackpoint modules, of which I preferred the trackpoint.
However I have since completely switched to using mouse keys, something that appears to be less common here. I definitely recommend giving it a shot. Now that I’ve gotten used to this I don’t ever want to use a dedicated mouse (module or otherwise) again.
Here’s a link where I shared my settings:
As for getting used to the device, don’t try and map every single thing at once and try and memorize it all. I did that at first and found I was creating headaches for myself. Map things as you find yourself needing them, and be prepared to tweak the layout until you find something that fits your personal comfort and usability preferences. I’ve had my device for a few months now and I haven’t touched my layout in weeks.