Bob, I have no problem creating split tones with just sepia then selenium on MGIV. Gold can be used as you say to warm up the sepia toned areas to a peachy color, but can be overdone in my opinion.
Have you thought about bleaching and re-developing in a re-developing toner such as Eddie mentions in his book "Creative Elements?" I do not have the book in front of me now but I believe the bleach contained 10% hydrochloric bleach and then he re-developed in a developer containing mostly metol. I will have to pull the formula up later. Its in the back of the book under re-developing toners or redevelopers. He claims it creates a bluer color on MGIV, which he says will go even cooler after selenium. This is something I want to try for sure just to achive a truely cold print tone. But I was thinking, after fixing and a wash, bleach and re-develop in this cold tone re-developer, then selenium first to cool your lower midtones and blacks even colder, and then sepia tone just the highlights for a hint of warmth. Just a thought.
As of now, I'm getting a nice split with sepia toning ever so slightly first then selenium toning for a short time which warms the sepia tones up a bit more and cools the shadows just a bit. But there's a chance that using Eddie's bleach and re-developer formula may create a split closer to what you're looking for. I try to stay away from toners and dyes, which are not archival.