The problem with the Biesmeyer fence system type is you will get a parallax error if you view the line on the tape from any angle rather than straight. The other problem is making small adjustments in-between lines.
I used to do my adjustments a little differently with an indicator which lean me to make this. I turn on the magnet and set zero anywhere on the dial I wish. Now I can make a .005 move if I want to or I can go back the the original.
It is a great way to get the fit when inserting a piece of wood into a Dato. Just an example is to cut a Dato with a stacked set, lets use 5 /8th stack for a lack of any other size. I find I use a digital caliper I bought from Menards for around $20. Probably more now it has been a while. The Dato width is measurable and the lets say a piece of plywood for a lack of anything else is also measurable. Again it is hypothetical lets say the difference is .065 difference. Move the fence .065. Chances are is just right that it will still to tight. Which in this case put the indicator back on and move the fence what ever you want it. The distance between lines is .001 so you can eyeball .0006 if you want.
Another use is with a tenoning jig. After the first initial cut is made the jig can be adjusted accurately by again using the dial indicator. the jig can also be used to make sure the jig is parallel with the miter slot.
Although I changed points for the next, it is a way of checking or setting you miter gage to 90 degrees. You will have to trust me on this one but I checked out both of my Starrett 12 inch squares on a CMM (Coordinate Measuring Machine) at work and both are within .001 runout in 12 inches. YOU move the miter gage in the slot and if your gage is off , how much. If your gage is adjustable it is easy.
And lastly my thin rip jig. Because the piece I had handy was a little thin I had to shim it up for the indicator to contact it for the pictures. The point is a little over 3/4 of an inch off the table. I cut the board to establish the distance the fence is from the blade. All my regular saw blades produce a 1/8th kerf. ( .125). Let say I want to cut a few strips 1/8th wide I move .125 (1/8 for the saw kerf) and .125 ( 1/8 for the width of the strip I want. When doing something like this I like to make it so the needle make about one revolution. I reposition the indicator and set zero and then both the fence with the wood is moved until it registers at the zero point and the next cut is made. For 1000 parts I think I would find a faster way to do it but for 15 it is the way I do it.
It looks like I moved it .165 in for some reason in the picture.
I hope I have helped.
Tom