G'luck with whatever route to decide to take. A well sorted suspension is an awesome difference to experience.
And to answer your last question before I check outta here, yes your body weight does make a difference in how you setup your suspension. "Weight" in essence, is exactly what your suspension is managing.
The weight of you, the weight of your bike's frame & engine, the weight of your gear, passengers, exhaust, etc.
Certain parts of your bike are not carried by the suspension however, such as wheels, brake rotors, and the like. You'll hear the term "unsprung weight" thrown around, and that refers to exactly these pieces, as they are not riding on the suspension.
First and foremost though, read-up on setting your "sag" or "preload". This is the baseline adjustment you'll need to make, before you even worry about your damping rates. If you're a pretty large dude, you might even look into different springs more suited for your weight. It's not
entirely necessary, but if you have the money to spend on it, and you only want to do it once, it's worth looking into. Clarkie said it best, in that it's not a black-art. You find the setup that you like, based on your style of riding, and that's that. Some will lean toward a comfy and plush ride and others will want their bike dialed to feel a real connection with the road/track; it's up to you.
Like I said though, good luck. And good-lookin'-out for even
wanting to sort your suspension, and not focusing on power gains.