Replacing Powerbook HDD...Startup Drive/USB?

Hi all,
I was going to start the process of replacing the old hard drive in my Powerbook G4 1.67 today, and started looking through the SuperDuper! instructions and noticed that it mentioned the following:

USB drives cannot be used as a startup drive for PowerPC based
Macintoshes, regardless of the program used. On top of that, USB drives
have a large number of limitations regarding speed and – even if USB 2.0
Hi-Speed rated – can slow down to USB 1.x speeds when used in
conjunction with slower devices.
So, if at all possible, please get a FireWire drive!

Now, I have no experience with replacing/copying HDDs at all, so the terminology of a Startup drive on a laptop has me confused. What I had planned on doing is using SuperDuper! to clone my current HDD to its replacement in an external ATA case, via USB, as the case I purchased doesn't have FireWire. Now, since I plan on marking this new drive as bootable so I can just swap it out, am I SOL because I don't have FireWire, or am I only SOL if I planned on using the drive as an external startup disk?

Hopefully the above makes sense. I really appreciate your responses, and any other suggestions you may have for a first-timer doing this seemingly daunting task.

EDIT: I just switched USB plugs and now it works fine...I guess one of my ports is more finnicky than the other.

So...I've got the new Seagate HDD in it's enclosure, and plugged in to my PowerBook via both USB cables to give it as much power as possible. I can't see the drive through Finder, but it appears under Disk Utility. So I figured that I need to format it, but whenever I try to format or erase or partition the drive in Disk Utility it gives me the beachball continuously and the status bar keeps cycling on Creating Partition Map. I've been gone for two days, and when I came back it was still doing the same thing. I have a feeling that it shouldn't take this long, but there are so many places where the problem could lie I don't know where to start...

Ideas?!? Thanks!