I have mine set to the highest value (10).
If you have the toolkit for the bike there is a special wrench for it with an extension.
It's easy to do yourself, the higher you go the harder it is to turn the wrench but still easy enough.
Something like 7-8 is probably enough. I set mine to 10 because im scared my tire might make contact with my licence plate again.
I watched some Dave Moss stuff and realised my 2018 650F had no static sag and not enough rider sag. It was set to the standard 3! So I backed it off 1 to 2 and the bike was a different bike and the tyres went from awful to predictable and pretty good. I'd recommend start low(ish) 5? as your a big guy and ride your favourite road then gradually increase. I had too much preload and it overwhelmed my front suspension which is pretty soft on the CB650F. Atleast we can only screw up one setting my Ducati was fully adjustable front and back and I could never get a happy set-up for all conditions!
Im 180lbs and tested it all out for a few days each (without measuring sag) to feel the difference. To be honest 1 felt different (bouncy), 2-6 range all felt the same (neutral) and 8-10 range felt the same (stiff). Wasn't anything noticable with the in-between clicks. Ended up settling on 4.
It's always been a thing on race bikes to jack the rear end and drop the front. -Is easier on bikes with clip-ons. Doing that might make you faster in the short term, but it's just a band-aid. Having a quicker turn in seems nice, but you'll be riding a twitchier bike. Setting up a condition you have to ride around is never a good idea.