Just wanted to report back that this was really good!
I did not halve the hens -- cooked at 325 for about 1 hour.
The kids did not like the sauce as much as I did -- likely I would reduce or omit the Worces. and the Dijon mustard to suit my kids taste.
I did use Cognac. Could have used DH's really expensive Scotch/Whisky, but I stopped myself . . .