R. Sickbert wrote:
There is some very interesting reading in the Mason Dixon forum under the topic, "Worst option". There is much in it about the Artillery Capture option. I think it will answer all of your questions along the way.
Your questions as I see them answered:
The enemy capturing your guns does not have to crew them to use them. You recapturing your guns must re-crew them to use them.
The enemy capturing your guns must garrison the captured guns at game end to get the VP.*
*unless they blow them out of existence with their own artillery where upon they get the permanent VP at the moment of that event.
I might amend the word "garrison." It implies troops. To receive VPs, you need only use a leader, or even a supply wagon.