Thinking along the same lines as Nige, I would use a starting time of 6 minutes at 68F.

I got developing times from the J&C chart for Ilford ID-11 and Microphen. Then I looked in the Ilford charts for Delta 400 rated at 200 in ID-11, Microphen and DD-X. J&C 200 was a pretty good match with Delta 400 rated at 200 both in ID-11 and Microphen (5 & 7 minutes versus 6 & 7 minutes). DD-X and Delta 400 rated at 200 is 6 minutes at 68F.