You can just download the default grbl package to your arduino and it works out of the box. You then send gcode commands from your PC to the arduino to turn the stepper the required amount. Installation instructions are here: https://github.com/grbl/grbl/wiki/Compiling-Grbl
Next. When winding 1000 turns there is no problem with +/- 1. My high power transformers have numbers line 10 and there can not be any error. My counters count tenths of a turn. That way some slippage in the shaft encoder is not as much of a problem. (some times I need to back up a little and fix a bump in the winding and then go on) A home made shaft encoder struggles with that.
There's no shaft encoder for feedback, and there'll be no slippage if you have a sufficiently-powered stepper motor. You can then tell it to turn the shaft with resolution less than a degree.
My first coil winder. Has 1/4 horse power and foot pedal speed control. You can't see the size but I have made 1000 watt transformers. About 40 years ago we added a speed reduction so I could pull heavy wire.
This is a small version I made. I need to have much less power. It runs from a bench supply. By setting the current limit small it will stall out the motor before it breaks the wire.
You can not see the 1/4 horse gear motor behind + counter with stop switch etc. It was built to wind degaussing coils for TVs. It also makes metal detector coils.
It makes coils as small as 4 inches to as large as many feet. I have many jigs. The one shown is about 2.5 feet across. I added red lines to show the shape of the coil.
guitar pickup forms are a rather odd shape for a winding machine, as they are about 2.5 inches by 0.3-0.75 inch and about 0.75 inch tall. the wire pull force varies a lot because of the aspect ratio of the coil.
Go to Gibson user site and ask. Several winders there. You can use a digital (optical) shaft counter but they aren't cheap. You really need variable speed motors so you can slow down before stop (sewing machine motor?) and GOOD tensioner. Google the Gibson vintage wider machines for soapbars.. IIRC the cheap commercials use a veeder type counter with a rubber wheel that runs on the winder shaft.