For what it's worth, this is how I make a split grade print:
1) With max yellow filter I run a step table of time to determine the least amount of time to obtain a hint of tone in the highlights.
2) With that time and filter I expose another entire strip of paper and then on top of that I do a step table of max Magenta filter to see what appears to be the best combined exposure.
Do NOT do the second exposure separate of the first because when you combine them it won't be right.
3) Now I make the first test print using the original yellow and the apparent magenta filter.
To go further is to tweak the print and that is purely subjective. The point is that the most important exposure, the one that the entire print depends on as accurate is the yellow. All the time in developer, the kind of developer, all the way through dry down will depend the yellow exposure.