Your hand is above the throttles? Shouldn't they be below?
737 SOP for the record...
If the call "set TO thrust" is made by the FO, my hand actually sits at the back of the throttles looking at the acceleration of the engines, hands ready to push slowly if needed (altough 9 out of 10 times acceleration is normal). I'm aware this is Boeing specific. However...
Once I make the call "thrust set", my right hand automatically moves up and if the FO doesn't remove his hands my hand will push his palm up and grab the throttles. The feeling of touch will make them remove instantly if they are taking too much time. The call "thrust set" is my call stating I'm taking over controls of the throttles. They should act according to it. Throttle control is an important "priority" at that stage of the takeoff and it should take some mental attention at that point so they should be "conscious" and not surprised my hand appears under theirs. They have time to remove if they don't like it, it's not a lightning speed action. But my hand needs to get on to the throttles.
BTW, in case of pilot incapacitation I was always trained to do this exact procedure as is the quickes and safest action, you only do it a lot faster and with more force. It is important to "throw off" the hands from the throttles, as people will use force and "grab with force" whatever they are holding to in case of overload or startle. This has happened already (in the simulator) to me, even with a very experienced pilot. And believe me, the "throw off" is an excellent wake up call to them to get them out of startle. I don't see how you can easily remove their hand when you come from above.