I do a test strip with no enlarger filtration on an area of highlight, and develop in standard Multigrade dev to find a base exposure that will give me the amount of highlight definition I'm aiming for.
Lith starting point, with a full sheet of paper always, is based on the "normal" exposure. I used to start 3 stops over with Fotospeed LD20 and Fomatone paper, but started using Moersch Easylith recently and I find 4 stops over base exposure gives a better starting point on the same paper.
This is in contrast to my conventional printing technique. I find split grade a more natural way of working, but it's a minimum of two test strips and two sheets before I've got a starting point normally.