Hosfac What I do is - when your item goes up into the launcher, it is in the upload section.
You do not have to hit upload on the bottom of launcher again (which does make it available to all others on the official sims 3 site).
If you just put a check mark in the item you uploaded, then click on Show File below, it will show you your file location for that item on your computer, you can get it from there without it being available to others on the Sims 3 Site.
Hope this makes sense.