I did some more research and here what I found out.
The poles are 6 inches apart (center to center) and have diameter of about 7/16 inch (can't find my calipers so this is just rough estimate, could be metric). There are universal headrests that can be adjusted to fit most of the cars , I'm assuming Camry included, but they usually come with build in LCD screen, in pairs, so the price is kind of steep at close to $300 at minimum , but if I could find a blank one (no LCD installed) it should be much cheaper and angle of those headrests is much more reasonable. I found one at E-bay for $30 plus shipping but it is nonadjustable one with wrong pole distance so my search continues. But there are solutions and it's just the matter of finding it for right price, so maybe others will have better luck than me. I also will take apart original headrest to see what can be done with it, but I wish I had a spare one just in case I mess this one up.