When I bought mine, there weren't too many options out. Mine was one of the first batch of "B"s that had the goofy "target/sporting use import points" grips on them, and I hated them with a passion. Since I had handled pre-B's before, I knew I would like the feel of the gun if I could have the right grips. At this time, even CZ-USA wasn't offering any different grips. The only choices were the goofy one, home-made, or Houge with the finger groove stuff.
I ended up trying home-made first. The gunshop I frequently spend too much money at gave me a pair of TZ-75 grips for free. I whittled away and got them to fit. Not bad, fit and feel were OK. The wood was a nice off-set, but it wasn't what I wanted.
I then took a set of Houge grips, and cut off the front panel. After a little sanding to get the contour perfect to where I wanted it (i.e. get rid of bumps left over from the finger grooves) they fit great. It's a very comfortable grip, and not this huge mass of rubber in my hands. The feeling is similar to the rubber grips on the EAA Witness if that will give you an idea of what it's like.
I'd avoid trying to modify Witness rubber grips to work. There was alot of work invovled with making the TZ grips fit, and the Witness grips probably wouldn't be any easier. The Houge was simple in comparison and gave about the same feel.
ETA: If CZ now has rubber grips for sale, I'd go with those first. You can always sell them off it they don't work. Since they are factory, they'd sell easy enough.