help w/ 2 things: copying modified files & coloring folders

So I've just been using Hazel for a few days now and I'm really loving it... (It took about 20 minutes of using the trial version before I purchased it!)
Anyhow, there are two things I'm not sure how to do:
1. COPYING MODIFIED FILES FROM NESTED FOLDER
I have a folder that contains a whole bunch of nested folders. Every time a file is modified anywhere within this subtree, I want that file to be copied to my Dropbox folder in the same relative location. The tip in this forum about running rules on subfolders was helpful. But I'm not clear on the best way to say WHEN A FILE CHANGES, COPY IT. I see there is a Date Last Modified attribute. Should I set that to in the past hour? Or will that cause it get copied many times during that one hour? ALSO: since I'm digging into nested folders, is there some method to copy a file to the same relative location in a different parent folder? This might be tricky enough that I'll have to write some scripts, huh?...
2. COLORING FOLDERS WITH CONTENT
Another scenario I have involves wanting to highlight a folder whenever there are files within that folder. I see there is a "number of items" attribute but that doesn't seem to do the trick. When I say "number of items is greater than 0", it sometimes thinks that this is true even when there is nothing in the folder. Is this related to hidden/system files? I've also toyed with saying when the size of the folder is greater than 0, but that also seems to not work as expected -- some folders have a size greater than 0 even when there are no visible files within it. Any advice?
(I'm new to Hazel *and* new to MacOS, so I might be missing some basic concepts about the mac file system...)
Thanks again for the amazing app.
Anyhow, there are two things I'm not sure how to do:
1. COPYING MODIFIED FILES FROM NESTED FOLDER
I have a folder that contains a whole bunch of nested folders. Every time a file is modified anywhere within this subtree, I want that file to be copied to my Dropbox folder in the same relative location. The tip in this forum about running rules on subfolders was helpful. But I'm not clear on the best way to say WHEN A FILE CHANGES, COPY IT. I see there is a Date Last Modified attribute. Should I set that to in the past hour? Or will that cause it get copied many times during that one hour? ALSO: since I'm digging into nested folders, is there some method to copy a file to the same relative location in a different parent folder? This might be tricky enough that I'll have to write some scripts, huh?...
2. COLORING FOLDERS WITH CONTENT
Another scenario I have involves wanting to highlight a folder whenever there are files within that folder. I see there is a "number of items" attribute but that doesn't seem to do the trick. When I say "number of items is greater than 0", it sometimes thinks that this is true even when there is nothing in the folder. Is this related to hidden/system files? I've also toyed with saying when the size of the folder is greater than 0, but that also seems to not work as expected -- some folders have a size greater than 0 even when there are no visible files within it. Any advice?
(I'm new to Hazel *and* new to MacOS, so I might be missing some basic concepts about the mac file system...)
Thanks again for the amazing app.