So with the new design of the forks on our bikes, instead of going with traditional lowering, could a guy just let the forks slide up through the trees an inch or so to compensate for the new height? As mine sit right now, they are barely poking up past the top of the tree with plenty of room to move if that's something that is safe/recommended.

You could. I did that for a while and then installed the progressive kit. The kit is nice and for $108 it was worth it to have it lowered properly and it's a bit stiffer so less dive under braking and you can go one inch or two. Sliding the forks up in the trees will only get you about 3/4 of an inch as the forks hit the bars. You will get some that say the fender will contact if you lower, but after several thousand miles with it lowered I have had zero issues and I have had the front off the ground (not on purpose).

I did know you could lower the new forks, what's involved in doing that?

yes, I'm too lazy to walk in the garage and look...lol

They just slide into the tree and are held in by 3 pinch bolts. There's no stop on top and I guess you could slide them up until they run into the bars.

I wonder if this causes vibration in the bars?

I wouldn't let them quite touch the bars.

So where's the pic of the 21?