Best high chair to put on existing table chair?

[Dipsydoodlenoodle]

I have attached photos of my dining room chairs.

Can anyone recommend a high chair that would sit on top of my current chairs? My main concern is any chair may be imbalanced by the cushion - hopefully you can see from the second photo that it's quite thick.

If I have to use a regular high chair, I have to use one, but for space purposes a one that sits on the existing chair would be most practical.

Thank you.

My chairs are padded but not as much as those pics. I have a chicco pocket snack and it started to tilt when DS lent to the side while eating. Not the end of the world but I did get a different high chair. I was also worried because it was leaving permanent dents in the padding. Sorry, not an answer but hopefully helpful anyway!