Please wait a moment! You are thinking one-dimensional. The Watt’s are not so important, the Amp’s are!
Your batteries are not 250V, “only” 4.2V a piece. You need a switch that can do 5A, preferably more.
Compare it with putting a 600 hp Ferrari in front of a plow: pretty sight but useless because lack of torque.
Just PM Simon at Convoy. He is a really nice guy, and will give you the best advice possible.
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As for the lenght of the switch: there is a “stub” under the rubber cap. You can adjust the feel with that.
Forward clickies tend to be longer. Chances are that in your case all of the stub has been removed.
Most of my reverse clicky switches work perfectly fine with a new rubber cap “fresh out of the box”.