I've seen photos of Japanese in "Gray," which appears to be Birchen (like Brown Red, but with the silver gene.) If you can get one of those hens, cross him to your Brown Red rooster, and the daughters should be Brown Reds. To get males, breed those females to either their father (100% Brown Red chicks) or to their brothers (50% Brown Red chicks, in both genders.) To actually get the right shade of brown or red might take more work, but this should give you chickens that are at least recognizably Brown Red.
If you need to work with your current hens, I'm not sure which one is the better choice, but you could probably work with either of them.
Breed the hen to your rooster, then breed daughters back to their father (the brown red rooster.) Hatch a bunch of those backcross chicks, and try to pick out some that are about right; then breed those among each other, or back to the original rooster. Compared with getting a gray (birchen) hen, this will probably take more generations, and hatching a lot more chicks, to get enough that are even close to the right color, but it should be possible.