Yep I probably wasnt clear so here goes-
The actual near collapsing Ive experienced has happened at highish wind
angles with a few meters of long period swell ie flying the PS at around 120 AWA then forward to 100s on the runs. Around 18 to 20 knots TWS gave us between 10 and 14 knots boatspeed which was enough variability to get the awa moving around alot.
In my mind I was rolling that out to deeper wind
angles and bigger seas with greater boatspeed changes but thats just theory at this stage and just on this boat.
Like I said I havn't compared like for like but a 20 degree wind shift is usually enough to collapse an untended sym spin whereas the PS luffs down to the wing, wing holds the bulk of the kite up for the wind change then pops back again as the boat slows. ie its still working where you should really have an asy up and that would still need tending I reckon.
If your on the helm
you can chase the awa a bit and lessen all of this of course but its usually too quick for the auto pilot and in bigger seas probably not a good idea. That said I havnt played with the AP sensitivities yet in these conditions.
The other thing we are touching on is the heavier cloth of the PS is still flying in light winds whereas the equivalent sym spin for 8 knots will be a lighter cloth and blow out in montes 38 knots (or well before) .
You can have 3 sym spins (heavy moderate and light) for the cost of one PS but in the squally conditions like Monte says are you really gonna bother with spin changes?
From memory Django has a PS on his 380 and we see from his earlier post he now has a kite on a pole for races - hes the man to comment - Django where are you??? (and dont forget to tell us about your new mainsail
Sorry also to the OP - your not gonna get a black and white answer as per usual on CF