Your wife looks beautiful. You are a lucky man.
I'm a foot tickler, and also more of a full body, spread eagled tickler. Your wife's soles are not visible in that picture. so someone who is a hogtie tickler would probably hogtie her and get her private areas or her backside which is exposed from that pose.
In another pose, say, spread eagled, I would get her soles first, and then turn her over on her belly and get her back.
I like tickling with fingers, and also things like vibrating electric massagers, etc. Those things can seem unbearable
Hope you like my feedback.