Hi Eddie,
I'm new here today too and while I'm no current "feet-in-the-fire" Mac Pro like some here, yet I'll offer a few tidbits that you may consider.
(1). I wouldn't undertake an upgrade to a later version of OS X. As I understand it, you'll encounter a performance loss over your current version (I'll attempt to attach images from
http://www.jcsenterprises.com/Japamacs_Page/All_Things_PPC.html concerning this possibility, to this post.) AND, according to another Apple source your version of OS 10.4.11 is the Maximum OS allowed on that machine (if I've gotten that right, also a possible .pdf attached here.)
(2). I recently acquired a PowerMac G4 1.25GHz DP MDD that I intended originally to wipe and install only OS 9.2.2 on, because of a certain affinity for the stability of that particular OS (not unlike the majority of those persons here supposedly). However, lured by the sirens' song of newer versions of software that I did not previously possess and the dreaded OS X, my quest has been to revert this MDD back to OS 10.3.x. while also keeping OS 9.2.2. (We'll see if I actually do this reversion or if I follow my own advice, i.e. "if it ain't broke, don't fix it".) Currently running OS 10.5.8 and OS 9.2.2. and yes, they're both on the same drive. Yes, feeling a bit schizophrenic but I simply choose from which OS I want to boot from, or can run OS 9 within OS X. (Yes, I've backed everything up before I begin to "clean/glean".)
I have installed a Firewire/USB combo PCI card to enable USB 2.0 and Firewire 800 (should I ever use the 800 Firewire), but the standard USB 1.0 ports made my back ups too painfully slow. Picked up the SIIG combo card on eBay for $30 bucks.
Also: Beware the video DVI notation for the video card, because if it's like mine, it requires the Apple Display Connector (ADC*) to DVI cable. Apple's ADC* is a proprietary connector based upon a regular DVI connector. Look closely. I usually run two monitors so I'll just slap another video card in a PCI slot.
I just found what may be the actual install/restore software for this MDD here today. It notes "single CPU" only, so I might be out of luck anyway... but I'll continue to look for yours as well. (Now maybe someone else will chime in here and say they know exactly what you need?)
Anyway, I've ran on enough here. Hope some of it helps you and forgive me if I've offered anything you may have already known. Now, let's see if I can attach anything to this...