That script looks good i'm gunna have to give it a go some time.
Although what i came to say was, I just did my first LIVE HDD install and i like it, made partitions fat32, ext2 and swap with part manager, booted usb version extracted bt3final_usb.iso to fat32 ran th bootinst.sh made to usual changes to enable persistent changes and restarted from HDD.
HD install now has all boot options and th pretty boot screen.
From what i've found BT3 seems to run better as a live install (auto mounting in particular) and now to install new apps i just gotta drop .lzm's into modules folder while its in its compressed state.
Slackware just got slacker.