Thanks for all of your thoughts and opinions.
I've just dumped in another quart of RK HD 30 makeup oil and will run this fill out to 4K or another three weeks or so. Dumping the Defy at 3K seemed a little foolish since the oil just went in on 4/17 and the car is driven under very easy conditions. I mean, how much easier than twenty five miles up a moderately fast two lane does it get? Also, a couple of quarts of added oil out to 3K will certainly refresh what's in there now.
Anyway, I'm leaning toward the Delvac 15W-40, since I'd like to give it a try.
According to the OM, this grade is good down to much lower temperatures than those I'll ever start this winter-stored car at, but then the OM also recommends 20W-50 down to about 14F. These engines must have some stout oil pump drives.