I don't have any experience to share, but the 1st suggestion that comes to my mind is to try CCM's Red NB colorant. It's very Red, and it seems like a little goes a long way, so it's potent. I have it, and have only added a drop or 2 in different mixes to get a slight "Red-ing". I'll be working-up a Red color for Saltwater soon, though...Red w/ Silver flake.
I wish I could help You more, Bro.