[davebarnes]

Gelco,

"Will the above drives work for the Macs I have?"
YES.

"Do you recommend I buy a RAID backup device for each of the Mac or the above is enough?"
Don't spend the extra money on RAID. If you are going to be serious about using a RAID, then you need to use RAID-5 or better.

"There is a QUAD version of the OWC drive with eSATA interface."
Buy the quad. Just in case. It is only $10 USD more for the two sizes you mentioned.

"any other advise or suggestion you can offer?"
YES.
You need to buy larger drives. Why do I say this?
You need to have space on your external drive for both types of backed up data: SuperDuper! and TimeMachine. So, your external drive needs to be almost twice the size of your internal drive.
Personally, I would buy a quad 500 and a quad 750 as they are only $176 more for the pair.

,dave