So I've been doing a little research, and this is what I've found. Tell me if this sounds right and sensible:

Transferring points from AMEX to DL miles at 1:1 ratio
for JFK-FCO in Aug. it's 100k miles coach, 250k miles business/first
This is opposed to about $1275/127,500 AMEX points coach; $3330/333,000 AMEX points business

The points/miles difference doesn't seem to be much in coach, but seems significant for business class. Does anyone know what business/first means for the Delta SkyMiles vouchers? Will I get seated in business or first class?

Now, if I use DL as opposed to CO, do I get complementary elite upgrades? For int'l travel it seems like the answer is no, which is disappointing.

Is there a better way to make use of my points than doing the above?

I'm really appreciating the help here. I don't normally have the time or patience to spend surfing the web for the "best deal," and typically pay for it. But this info on how to navigate the Centurion/airline world for travel is great.