I got a good mag calibration, with one battery (a 4S 1800 mah) but then again got slightly yellow status (running 5-8% error rate most of the time) when I switched to a slightly smaller battery (a 4S 1600mah). There are several inches clearance between the battery and mag, and I made sure to run the battery leads in the same position. Could the difference in calibration be from just the different battery size?
Generally, you are running such low current when the motors are off, that it just doesn't even see the battery. This assumes that battery wires (and others) are twisted properly and battery is several inches from your mag. I presume you have an aux mag and have your mag settings set to "aux only" (important (you don't have to recal mags just to change this)). Mags should be generally green. Movement during mag calibrations should always be slow (say take 3 seconds to get from one position to the next) for best calibration. By force of habit I always set my auxmagsettings and revocalibration .mag_bias to 0,0,0 and auxmagsettings and revocalibration .mag_transform to 1,0,0,0,1,0,0,0,1 before mag cal, but that shouldn't be necessary in 16.09.
I went ahead and tried a position hold on both batteries. Position hold was pretty successful, but it did a bit of a pendulum swing fore and aft that seemed to keep getting larger.
Was it toilet bowl or just pendulum? Anyway, these are a sign of bad mags. It could be calibration and it could be wires not twisted / routed well enough. If you are seeing a lot of yellow with motors stopped, I would focus on mag cal until that is better.
I had previously done an AutoTune and when I switched to "bank 3" (where my AutoTune settings were stored) it seemed to reduce the oscillation significantly, although those settings are too touchy for me when flying LOS.
Assuming you are flying ATtitude mode... Either the AT tune is good or bad. If good, then it should be very "locked" to exactly what you ask it to do. That should feel better, not worse in LOS. Is yaw the main problem there? If so you can reduce the yaw rate / rate mode response yaw to tame that down. For pitch / roll you reduce the max bank angle: attitude / attitude mode response
Both batteries responded pretty much the same, so I feel like the "yellow" status wasn't significant enough to cause me any real issues.
Mags are important and should usually be green.
I had set the position hold to use "altitude" assist.
I suggest VelocityRoam over PH. It's the same when sticks are in the center and it lets you drive it around. "Altitude assist"? I am guessing you mean "Assisted Control"? That is generally for adding "PositionHold" to non GPS flight modes. I don't know what it does to PH. I haven't used it. You might try VR with Assist off.
As a side note, the only thing I had to watch out for is that when I switched out of stabilize mode to position hold, the throttle was way out of whack. When I switched INTO position hold, I had to add a lot of throttle to hold altitude. ... Right now I'm flying in stabilize hover @ about 30% throttle.
Yes. Any mode that stabilizes aLtitude uses 50% stick to mean "don't change aLtitude". If you are hovering at 30% throttle your props may be too big unless you know you built a real rocket. What motors props battery weight are you running at 4s?