Three thoughts:
DEFINITELY:
No matter what operating system you have, there will be a Device Control area where you can switch the mouse's handedness. DO THAT. Your speed of entry will be improved, too, as you will not be switching back and forth between the number pad and the mouse -- your hands never leave the surface.
As well, forget about the $100+ mouses -- the thing you're purchasing is a framework for the actuation buttons/switches. No matter how cool the framework looks (and across the dozen or so brands), there are still only 2 or 3 manufacturers of the actual switches. Aside from the junk mice, a $50 mouse has the same switches/sensors as a $150 mouse.
Last, as a mouse pad, I use a $5 plastic cutting board from Target (I think). It stays in place, it reads (laser-wise) as flat, and it protects my antique desk varnish from the sweat which would bleach it out in a single summer. ("Ewwwwww!") It's so thin that the heat from my hand will warp it over a few months, so I periodically roll it up opposite the warp, and leave it behind a wall monitor, to "cure" back to flat. So, mark me for 2x$5 mouse pads, rotated as needed. ("Cheap bastard!") You betcha.
Okay -- a bonus: if you have tendonitis/tendonosis, do yourself a favor and find some Glucosamine HCl (not the sulfate, but the HCl), and take one pill a day for 3 months, and WOW will you feel a lovely difference.