I also have G11 with AT10RC which is about #40 in total.
My RMS is between 0.6" and 1.2", depending on conditions. I am fairly happy with my images.
Here is my astrobin page, showing my images: https://www.astrobin.com/users/avarakin/
What is the problem with your images exactly - elongated stars?
Are you using OAG? With your FL, I would strongly advise switching to OAG.
Your issues may be caused by flexure in different components between the main camera and the guide camera.
You will have to upgrade your camera to 174 chip in case if you go to OAG: 120 chip is tiny for OAG.
PHD2 works great with Kstars for me.
I try guider of Kstars once in a while and still revert back to PHD2: PHD2 is much more robust.
Did you try collecting unguided logs from PHD2 and analyzing them using PHDLogViewer?
Once you do, you will see your periodic error and the components of it. This will help you to troubleshoot the culprits.
I doubt you need to increase micro-stepping - 2130 chip has interpolation to 256 micro-steps.
Your motor might be the reason for your problems too - it has pretty low torque.
Look for threads here, there is some very good motor from Oriental motors. It is costly but has much higher torque.