It depends on your grip. I use a high grip with both thumbs forward. The thumb of my shooting hand rests on top of my support hand?s thumb.
When I shoot 1911/2011?s my shooting hand thumb is riding the safety, mainly to keep it down. But due to the angle difference on the CZs I don?t do that when shooting the S2. For me, the heel of my support hand can make contact with the CZ?s wide thumb safety, and in the past it?s bumped the safety up while shooting.
So when I got my S2 I actually liked that it came with the flat safety, and have been shooting/dry-firing it like that ever since. I actually prefer it to the wide thumb safety I have on my 75 Shadow.
IMO, thumb safety on a DA/SA gun in Production is not needed. It never gets applied during a stage, so being flat and not in my way is the ideal situation.