i posted this question in the 'how to backup OS' sticky, but maybe more visible here:

i formatted and installed snow leopard on an external FW drive, booted to it and installed pro tools 8 to test it out as it wasn't working after i upgraded to SL on my iMac. it worked, so i then migrated over all other apps, settings etc. to the bootable FW (CS5, FCPS2 etc etc.) to test if all would work and play nice together. All is good and i actually set it all up to my liking.
Now i would like to wipe my internal drive (making it one partition instead of 2) and simply copy the external to the internal using disk utility's restore.
my questions are:
1) should i do all this by booting from the external and use disk utility, or should i boot from the install disk > disk utility?
2) when using 'restore', do i have to rename the internal destination drive the same as the external ('Snow Leopard Fire')? if i name the internal 'mac osx' will it mess up the apps i installed on the external?
or is there a better way to accomplish all this? (ie: wipe and fresh OS install on internal, then migrate all apps and data from external bootable drive).
thanks!

I use Carbon Copy Cloner for this.

Format the drive with Disk Utility, then use CCC to clone the external to the internal, shut down, disconnect the external & reboot.

thanks for your response, but as i am trying to learn disk utility better with the help of Robert Lane's sticky, i would still like to use disk utility and my questions remain.
to quote from the sticky:
third party programs offer a "certain level of automation, but from my perspective it's always better to have complete control over the process rather than *hope* the automation does it right."
i was hoping for a response from Godzilla himself, but he may be busy destroying Tokyo...

I use SuperDuper for this purpose. It's more fool proof than booting from your OS X DVD & using Disk Utility. It's free for the whole disk cloning version. However if you insist on using Disk Utility then I am sorry but it's so long since I used that to clone a disk that I would risk giving you wrong information were I to dredge up instructions from memory which is why I always recommend SuperDuper as it is easier & safer to use.

i ended up taking the plunge and booted from the install disk, used disk utility's 'restore', restored from the external drive, naming the destination internal the exact same as the external. it worked! FCP and other apps have not lost connections (maybe because the drive is the same name?) and no program has asked for authorization or serial codes/numbers because of the 'new' drive's different serial number.
i am putting it all through a workout to discover any problems, tweak and install updates that slipped by me while building the external drive- before i clone this internal and install it on my MBP to have 'twin' computers.
not sure if i am doing this all the best way... but it seems to be working (except for pro tools 8 being a temperamental, buggy pain in the ass...). what a time consuming process, all because i bought one new piece of hardware that started a domino effect of being forced to upgrade everything! i seem to spend more time teching than actually creating...