Size doesn't matter when it comes to performance, only resolution. More pixels = more processing. You can change the resolution and settings, but it is best to run LCD monitors at their native resolution for the best results. Greater size at the same resolution means the pixel density is lower, so the picture will be less sharp as you go up in size at a given resolution.
Typical rules of thumb for 16:9: 21-24" 1080p, 25-28" 1440p, 28-34" 4K to maintain density. 21:9 muddles things a bit, but basically the same applies. a 29" 2560x1080p is about as big as you want to go. 34" should be 3440x1440. Not really any way for 4K ultrawides to be properly run yet, so doesn't really matter.
IPS provides good color reproduction and good viewing...