Hi SDTTA, yes of course this is more difficult when a player swaps between pimples and a normal rubber in the rally. In this situation it’s important to really slow down and focus on which side is which, before the game be sure to ask to see their bat so you know which side is pimples and which is the normal rubber.
Usually players who twiddle and change the bat around a lot don’t attack much and try to force you into mistakes by confusing you with different spin, so it’s key to stay consistent and try to keep the ball in play. It does take some practice and getting used to quickly seeing which side they have used but of course what you are waiting for is a weak ball perhaps after a push to the pimples that you can come in and really attack strong.
Also focus on making it hard for them to get an easy ball,so playing into the crossover or their body is a great tactic against these types of players as well as really mixing up your serves and the speed of your shots to break up their rhythm.