For starters, this is my External Hard Drive (Link

Okay, I've been using BT3 for a couple of years now, and I've been wanting to give BT4 a spin, however I don't want to burn a DVD for it.

Also, I only have a single 1GB Flash Drive so that won't work.

I do however have a 500GB External that I use for every day storage. It's got ~100GB full at the moment but I don't want to delete any of that stuff.

Is there any way that I can partition some space for BT4 on it, preferably with Gparted? And then would it even be able to boot properly if I do this?

*Also as a side note, Should I do Live USB or Persistent USB when doing this? Which do you think would be better?