Well, I am a sort of clumsy builder who OVER does almost everything during the build, so I can't address weight reduction. But I think that from a purely theoretical standpoint that losing a pound of weight will equal a pound of thrust when purely vertical, becoming exponentially less noticable as you transition to level where the top end speed will be limited by the cumulative components of the various flavors of drag. The extra drag caused by incrimental weight is a tiny fraction of the total drag at high speeds.

It's also worth noting that completely independent of thrust, one pound saved is the same as FOUR pounds during a 4G pull, reducing the induced drag a lot and helping the model retain energy. In full scale aerobatic competition, I've seen folks in the upper classes sweat about 10 pounds of extra fuel (!) onboard a 1600 pound airplane cus they don't want to lug it around during the sequence.