We can adjust to warm colour temperature and lower the backlight but still may feel a bit headache or eye strain after continuous use like 6-8 hours. There isn't any other technology like blue light filter etc.
Switching from 27 to 43 inch is a major change, so it may look odd for a couple of days. Earlier I was using 32 inch Full HD tv and switching to 43 was very noticeable. I feel size won't be an issue as we have 43 inch monitors available and you may find it more comfortable opening multiple applications on the same screen.