Okay pics
:
Here is ds3 in the Vivo on the left and TB on the right, how he would normally sit and hold his head (a little forward of the back of the headrest)
And here he is with his head back, like it would be when he sleeps. You can see a difference on the Vivo but the TB head rest is so small in comparison that it is hard to tell.
And a side view so you can see how much more supportive the Vivo is.
Here they are side by side and back to back in the house. Both are in the same position he would use in my van in the side by side pic. The TB has the head rest all the way up and the Vivo has 2 more clicks. It looks like the TB is adjusted higher but it is because the TB sits higher than the Vivo. I lowered the headrest 1 click on the TB for the back to back pic so it would be easier to compare the two.
And then a view of the 2 from the side.