I'm pretty new to SGP but I have finally gotten my focus under control and now have a fully automated system. I finally sat down and figured out how to get my step size and it really does work.
10 might be a little low to start. I started with my coarse at 150 and my fine setting at 30.
But if you follow along with that way they tell you do it you can figure it out.
I'll try to put it in laymen terms and I'm sure that others here will give you better ideas but try this.
Start with LUM and get it focused as best you can.
Once you have that do this.
Shoot an image with the exact same settings you have set for your exposure in auto focus. Something like 10 seconds at 2x2.
Write down the HFR Value and the IN Focus number that it is set at.
Start looping at that same exposure and while it is looping start clicking on your fine or coarse focus buttons until the HFR number is 3 - 5 times higher than the number you wrote down. I split the difference and go for 4 times.
Take your time here and let the images download before you click it a bunch of times because you might run right by it if you go to fast.
Once the HFR is 4 times higher than the one you started with stop the looping and don't click the buttons anymore.
Now Take the new IN Focus number that is showing and subtract the original IN Focus number from it.
Multiply that number by 2
Divide that number by the number you have set as your "Auto Focus Data Points"
(those data points can be found in the "Auto Focus Options" That's where you go in the control panel and click on focus and then click on the word "set" next to the "use auto focus" tab. The number will be the 3rd from the top. You probably have it set to 9.)
After you divide that number by your data points subtract 1 from that number and that will give you your step size number for that filter.
Put that in for your step number and run the auto focus. Remember that the number will be different depending on what filter you use. What I did was ran it on all of my filters one after another so the temp and conditions were the same for each filter.
That will at least give you a good starting ground for setting up your presets in the filter focus tabs.
Good luck I hope this works.