If my friend did a clone from a bottom of a cherry...

Agree with the other person who answered. The clone should be a genetically identical copy of the mother plant... but after rereading your question I think you’re actually talking about the mother plant’s yield. Your plant shouldn’t have a huge drop in yield from taking one or two small clones. In fact, if the stem you take is low enough on the plant it could(not will, it could) increase your yields some because the plant is no longer sending energy to that lower bud site that wasn’t getting very much light to begin with. If you haven’t ever taken any cuttings or defoliated your plant and don’t know how it will respond to such stressors, be cautious as you don’t want to over stress your plant. Cloning during flower is a bit more difficult than in veg. Just be patient, keep high humidity during rooting and don’t overexpose the clone to light(something I’ve personally been struggling with). Try to take a clone with at least three nodes. Rooting times depend on your temperature, strain of plant, humidity, and other factors such as use of rooting hormones.