As an update, over the past few days I'd started thinking that if the vertical mice were too big for the tray, I'd might as well go ahead and buy a standard joystick (not the overpriced joystick-mouse I mentioned earlier) and use input programs to use it as a power mouse.
Well, today I decided to go look over at Office Depot to see if they had any set up for customers to try out (because the exact model I was looking at - the Logitech Extreme 3D Pro - they did happen to have in-stock). They didn't, but the price on it was nearly $10 less than it was online, so I went ahead and bought it anyway.
Even though I've been using it for less than three hours, there's only two real issues I've noticed:
1) I'm going to have to build the button remapping program (AntiMicro) myself because my computer is ancient. Most users that will want to try this won't have to deal with that because they're using computers that have CPUs which support SSE2 (note that this is *only* when I'm on Windows; the Linux version of the program doesn't have this particular restriction because of the Ubuntu's -dev packages of Qt5 having been built with compatibility in mind). This practically doesn't even qualify for mentioning, but in my case it does.
2) I was expecting it, but I do have to reach to grab the joystick. With my chair at its normal height and distance from the computer desk, this means that my arm is almost fully extended when I grab the joystick. Again, somewhat minor, in that the solution is 'get a better chair/computer desk'. In a pinch, I can switch back to the mouse if I need to, provided it doesn't act up.
Usage-wise, the remapping program can set the sensitivity of the pointer, so you can get it to approximate a mouse's sensitivity. It does put up more physical resistance than a mouse does when you pull on it, but I can see that as something of an advantage. The overall effect is less like a mouse's rapid pointer movement, and more like a deliberate gliding movement.
This thing has a lot of buttons to customize, so I have it set up with the trigger as a left click, the thumb button is the right click, the hat switch's up and down positions approximate the scroll wheel, and three of the four buttons surrounding the hat switch are set for Home, End, and middle click (the fourth hasn't been configured). There's also a throttle and six more buttons on the base that I haven't configured yet. So the button layout right now is not similar to a mouse at all, but it feels natural (and let's face it, pulling the trigger in order to click a link is really, really cool).
Ergonomically, the joystick itself is molded to fit the hand comfortably (and yes, this is very much a right-handed model; left-handed ones might exist, but I wasn't looking). The thumb button I mentioned is in a recessed area that fits the thumb well, and there's a small hand rest that keeps the wrist more or less aligned with the forearm when the stick is in the resting position. As with most joysticks, the forefinger naturally rests near or on the trigger, and with it mapped to the left click, this is the only button that uses the same muscle memory that a typical mouse does.
The base (really, the whole stick as well) is sturdy, with thick plastic feet. I do have to be careful when pulling the stick *too* far to one side, because it will lift from the surface of my desk (again, more a problem with the finish on the desk than with the joystick), but most mouse motions won't require that, so that should be a fairly rare thing.
Whereas a mouse will require the user to lift it up and set it back down if you need more room to move, using a stick does not - this may sound completely obvious, but it's very noticeable (and welcome; the lift-and-reposition technique has really been annoying me lately). Trackballs are also like this, from what I've heard and can assume based on their appearance and way you're supposed to operate them.
In short, it's mostly muscle memory and that automatic impulse to grab the mouse that needs to be relearned, but the grip and actual performance of the stick (once its buttons have been configured) are pretty nice. Any problems beyond that appear to actually be the fault of something else - mostly, the desk height/design I'm currently forced to use.
