WD 1 TB hard drive partitioning for optimal protools sessions

[Jared Brennan]

Greetings DUC folk,

I've been rifling around many forums, manuals, and various search engine's for a 'hold my hand through the partitioning for PT' to no avail...

Some background:

What I have is a WD 1 TB Mybook Essential Edition (7200 RPM); USB only, no firewire... When I first plugged it in Time Machine app took over. I've recently erased it and it only has 913GBs on it, which I am slightly curious if this would be the "empty state" size or if there is something else I don't know about this process as I am a fairly new Mac owner (and will never own another PC ever)- I wonder as such because my 2GB flash drive for school projects doesn't always replenish in empty space (as evident in its freespace size) when I trash & delete files. You cant see files on the flash drive anymore, but the freespace size does not return to its "empty" capacity... (I would also mention that I did not "trash" the 1TB drive but used the disc utilities area for erasing...)

Where I would Reeeeeealy appreciate some guidance:

Disclaimer: Since discovering DUC I have sort of pieced together answers, but have not found a thread with my exact question, and I want to make sure I am doing things right and not all halfassed...

1) Given my computer (iMac 24" 2.66 intel 2 duo with 640 GB hard drive) and the External HD I have at hand (though having read various threads I will expand upon storage goods when I have the $), should I partition this drive for PT?

2) I've read that partitions for this drive when being used for PT cant be larger than 150 GBs per partition- is this true?

3) Would it reduce effectiveness to have more than 2 partitions (like if I wanted to backup iTunes music onto external drive too, etc...)?

4) An explanation of/link to an explanation of partitioning for dummies and (more importantly) setting it up with PT and my iMac for optimal performance would be amazing and appreciated forever.

If anyone has read this far, this leads to

5) so I have my ex. HD partitioned, iMac/PT settings in order, so what do I do with PT session folders from before this new configuration? move them to HD obviously, but my main Q is whether or not there will be issues in opening these previous sessions once moved to ex HD or any obvious steps to consider that a slightly above novice like myself would overlook...

thank you thank you thank you. Im excited about finding this forum, and have picked up quite a bit looking through older threads