Power Mac - HDD upgrade advice needed.

Hello,

I have a dual mirror drive dual 1ghz PowerMac and thinking of hard drive upgrade. I have two IDE drives on the Mac right now. I use it mostly for loading DV video from digital video camera and working on iMovie and iDVD so the HDD speed (mostly encoding step) and storage are important.
I'm considering getting a PCI SATA card to put two internal SATA drives at the back carriages.

I have numerous questions:

1. Would this be the best setup in terms of speed and cost (i.e. should I consider SCSI, etc.)?

2. According to PowerMac manual the PCI slots I have are revision 2.1. Could anyone comment on, how much transfer speed would I achieve on PCI 2.1?

3. Would it be worth getting SATA II (3g) for PCI 2.1 slot, or would the PCI be the bottleneck and get SATA I (1.5g) instead?

4. I looked at several PCI cards but wasn't able to find one that explicitly states it is 2.1 - closest I've seen was 2.2. I understand that PCI 2.2 is a 3volts whereas 2.1 is 5 volts. Could someone recommend a PCI SATA (I or II) card that is compatible PCI 2.1?

5. Would there be any speed advantage in buying 2 PCI cards for two SATA drives as opposed to one PCI card with two SATA ports?

6. Should I be aware of any compatibility issues with SATA/SATA II on this Mac model?

7. Hard drive itself - how much would I benefit in terms of speed from 10k vs 7.2k rpm SATA HDD?

Many thanks,

David