So much for my desperate hopes the SWF saga would be finally over. Unfortunately, I did not have to wait for iDeMi's reply. After a month with the .5 beta without any problems, the dreaded double-chime of the SWF reboot returned. This is only a quick recap for the sake of continuity.
My hopes were quietly propped up by the lack of the usual daily notifications from the two SWF threads. Since people generally write more about problems than they do about the absence of such, it seemed there is a faint chance the solution might have been found, at last. Looks like it hasn't.
It should be pointed out that there definitely is a difference after the .5beta update in my case, at least. It has been a great relief that for a month my work was free of the daily SWF reboots, which I had mercilessly experienced for months before that. However, as I already mentioned in my first post .5beta update comment, it did not seem very convincing that a complete solution has been found, because the sleep state appeared different and not going to a hibernate-like mode.
For the sake of completeness, it has to be clarified that during all this time I always left the iMac to follow through the power management set period of display and computer sleep (5/10 min). Yesterday for the first time I used the 'apple menu' sleep command, which I used to do in the long distant past, before the SWF plague. It could have been coincidental, but having used the 'sleep' command combined with the passing of the arriving of 'autopoweroff' state, which most certainly invokes hibernation, appears to have caused this horrible SWF again, after otherwise uneventful and so much hopeful month.
Such a disappointment!