You have to look at your MAP tables. At high vacuum (low pressure) you can run more advance for a cleaner burn and better efficiency and better throttle response. At higher RPM under open throttle most people have found that about 34 degrees is where you get the most power. You can read a bunch in the L6 FAQ sub-forum about having timing set "all-in" at about 2500 RPM or various numbers around that. Meaning that it stops advancing and just hold at that advance number from there to the high limit.
If I was starting with an MS tune I might first just mimic a stock engine's timing curves. Nissan provides them in the Engine Electrical chapters. You have to do some translation. And the charts are in distributor speed so that's where you have to do the doubling. From back in the days when they had distributor tuning machines.
The early FSMs have an actual graph. Later ones have just a table and let you imagine the lines.
Here is 72 and 78. 78 would be like your engine probably if it's a stock 290Z engine. They have different options for different markets and different transmissions. Generally, lower advance is for emissions states, like CA. Reduced timing is cleaner. notice that they give the starting point, zero degrees at XX RPM. So the first entry shows vacuum advance starting at 200 mm Hg, and increasing to 15 engine RPM at 350 mmHg. Centrifugal starts at at 1200 RPM and rises to 17 degress at 2500 RPM.
It's like a mini general physics course. It can be confusing, especially since centrifugal is tied to crankshaft rotation but vacuum is just tied to air pressure in the manifold. Sometimes I still wonder if I'm thinking about it right.
It's easier to grasp if you have a stock distributor on a running engine with a timing light to learn on. Good luck.
1978 EE chapter.
1972 EE chapter.