Logitech M570 vs Microsoft Trackball Optical

I would suggest using trackball mouse if you have limited right hand space. logitech M570 is really comfortable for example. But the major issue seems to be that keyboard and how it is too wide, you probably should look for narrower keyboard. Maybe you could find tenkeyless ergo board and use separate numpad on the left?

I loved the Logitec at first, but the smaller size palm annoyed me after a few hours of play. I do prefer the larger palm grip on the Microsoft Mouse, but I must say.

The ability to program the 3 "extra" mouse buttons (3 includes the clickable wheel) is appreciated, and makes the trackball much more versatile, depending on your needs. I've got the buttons set to "Backspace," "Home," and "F5" (reload), which allows me to browse almost entirely without need to use the keyboard. Additionally, setting a function for clicking the scroll wheel does not limit or remove its scrolling function, which was a relief, and another great design choice. Overall, unless one was to spend considerably more for a specialized trackball of professional quality, the M570 is possibly the best among what's currently available

I have an original Microsoft Trackball Explorer, bought at Egghead Software in the 90s. It's worked great ever since then, but lately I've been having problems with the scroll wheel. Every so often the scrolling will go crazy for a few seconds, zooming down to the bottom of the page, or alternating up and down repeatedly. I really like it and I'd rather not replace it if I can manage it