Phew! Dodged the first bullet. sRGB is good.
Next step - you need to get out the prints you had at your last monitor calibration, and see if they still match your screen, or if they are now greener than the screen too.
Yes, I know. And Brian is going to flip his lid when he reads this.
This kind of stuff is exactly why he tells us never to put files on our desktops, ever.
Oh, that's annoying, isn't it?
Have you tried uploading a full-size photo to your site, then once it's there, downloading it again to see what size it is?
I've just done so.
But if you're dealing with a glare problem of your own, please start your own thread with it. These fixes are quite specific to each photo.
I'll answer this part. No. You only ever need your resolution to be such that the pixels are small enough to reproduce the smallest detail of your wife's brush work. And on canvas, this is not very small at all.