I just found out that the Tri-X 400 film that I had pulled from one camera and finished in another had been misscalibrated. The first rating was iso 400 in a Yashica T4 while frames 15-30 were shot in a Nikon FE and rated at iso 200.
How does this sound: Rodinal 1+24 for 15mins at 20c.
I do the film 1+50 for 13 minutes when shooting @ 400. For 1+24 (or 1+25) I would go for 7 min @ 400 or 4½ min @ 200. Try giving it 5½ and it will be almost in between. Then you will get slighty overdeveloped negs for the shots done @ 200 and slighty underdeveloped negs for the shots @ 400. Both will be printable without much loss.