Johnny has provided a good description - I don't actually hold a wa handle differently from a yo handle, tho, his explanation makes sense and I don't disagree with it.
I started using yo handles on German knives, and migrated my technique - I use what I call a hybrid pinch grip - I wrap my index finger around the front of the ferrule, and use the shoulder of the ferrule to lock in my grip. I use a variety of grips depending on the cutting task, but this is the most frequent. I don't use a typical pinch grip on the blade as I don't find it as confortable or gives me as much control.
While I love the look of your wa handles w/ the tapered ferrule, my only concern for my own use is how it would affect how I hold the knife. If there's too much taper and not much shoulder, I may find it uncomfortable.
I owned (and sold) a Hattori FH 270 gyuto - has what I considered to be one of the nicest yo handles, but it was on the small side. And the ferrule was taperd too small, and it was too difficult for me to wrap my finger around the ferrule and get a secure grip.
I hope there's something in there that useful for you. Cheers! mpp