"Please dont write over long or short fins. Flex or twist,Thick or thin fins. Sanded or not. G10 or carbon.
Please only what a spin out is, I wrote what I saw, and what I did to eleminate spin out.Sorry, that write I
Think its good that we try and keep things simple butt all parameters you mention have influences on spin out.
Putting it simply though (IMO) spinout is what happens when fin stalls; ie when it stops opposing downwind force and lets board slip down wind.
Reason for stall are many fold and inter related and hence diiicult to quantify. Aeration is simply but one of them. (But cavitation is not)
If you are spinning out very early try a thicker fin.(It will work at higher AoA encountered at slow speeds.)
If you spin out at speed try a bigger fin but check you have not affected your Vmax. ???