I think that the size changing arrows are very confusing. My preference will be a constant size one, pointing in the direction of the correction. To show the magnitude of the error, perhaps you can use arrow's color. Instead of white, they can be red/yellow/green. If you choose an intermediate size (perhaps not as large as you have shown here), they will be visible from far away. This way you will be looking for "two greens"
I second Rafa's comment, the size of the arrows should not change. Maybe have them in a size between the two presented up there in the screenshots so not too big not too small.
I would have the arrows change to a green circle when the polar alignment is within tolerances.
Kstars Mac osx
Odroid C4 / WO Redcat51 / CEM25p / ZWO533MC / QHY5L-II-M (OAG)
For the plate-solving in polar alignment, I wouldn't change the plate-solve parameters from what already works for you with normal align/plate-solve.
Personally, I tend to use Scale and Position if I'm using the Internal Solver, and I tend to disable (uncheck) them if I use ASTAP, and I tend to use both.
However, if plate solving is not working well, and other things look good (focus, weather), then I'd disable scale and position.
I'm not familiar with the "entering 0" advice, haven't heard about that.
I would keep both update checkboxes checked.
Yes, I think "nightly builds" == "bleeding edge builds".
I had the opportunity to test the "Plate Solve" mode yesterday as my PA was off by more ( > 2 degrees ) than my CCD field of view but the "Updated Err:" stop updating/refreshing after a few iterations and even disappeared. Any clue as to why this happened?
"Note that, since knobs may be moved during exposures, some images may have large star trails and plate solves may fail. Be patient and allow the system to capture a clean image before relying on the error estimate."
Here's a thought. Stellar Solver is capable of running parallel plate solving operations on the same image with different parameters. But given already established parameters, image scale and location, it might instead be possible to use parallel solvers on different images as the refreshes come in. This way if there is a bad frame, it can automatically be aborted if a more recent frame solves first. Just update the position with the most current successful solution.
INDI/KStars on Raspberry Pi 4, 4gb
Raspbian Buster with AstroPi3 script configuration
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG/ASI120mm @280mm Guide Scope
Waveshare Stepper Motor Board - DIY Focuser
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.