Altitude Hold Fine Tuning?

[AndrewJohnHawes]

I tested the altitude hold today. Previously I have had pretty good results with the position hold.
With the vertical gain set at 80% with the Logo 700 (default I think), the helicopter shot up and down about 1m or more, quite aggressively, before I switched off the function.
For about 10 seconds or more it just climbed and fell this distance without settling! Is my gain too high or too low, please?
I understand that the aggressive motion could be interpreted, according to the explanations, as having too high a gain, but the precision at about 4m altitude was poor. The day was quite windy with direction quite variable and gusty.
Thanking you for your help here.
Andy

[AndrewJohnHawes]

It seems from what some other altitude hold questions have suggested and in ensuing discussions, that I should probably reduce the vertical gain if I am seeing such 'Visible' altitude changes (about 1-2m).
I note that the Geolink tuning advice suggests double checking servo-arm centre positions and ensuring swashplate levelling. I did both of these things, especially with the RD Lohr swash levelling tools and feel it is quite spot-on. The only discrepancy from the advice involves 0 degree pitch on both blades. I have blades which require very slight individual pitch tuning to maintain accurate tracking! (Maybe I need to buy some more expensive blades, but I have always found that even with good/best blades, that dynamic blade tracking adjustment is required!
I tend to fly with relatively low head-speeds, although I need to physically check the exact rpm and change settings with the Hobbywing telemetry which requires some further tweeking. Maybe I need to up my head-speed a little more?

[AndrewJohnHawes]

Reading further questions, I will reduce vertical gain by 10% at a time and then fine tune.