Glad I could help (I went through many of the same frustrations)!
What you did so far doesn't install Tiny Core to your usb, it just puts the extensions and the save file there (yes, sda1 was the right thing to put for that -- forgot that part). If you want to be able to boot off the usb or hard drive without the CD you have to do an install. I've never done that (like I said my PC can't use it) so if you want to try it somebody else here should be able to help (see TCLFAN's post).