Jonathan, hate to say it, but you're probably just lucky that you haven't a sporulation event yet. I've gone years without stuff happening and then BAM, it happens like 3 or 4 times in as many months, and then nothing again for months to years ....... basically it's like speeding and getting speeding tickets. Yes you can probably avoid getting tickets by watching for speedtraps but the odds are that sooner or later you'll miss that one speedtrap and then you have a speeding ticket.
The only real way to prevent big sporulation events in your tanks is to be religious about pruning, and thus if it happens it's maybe only a small event and thus not really a big deal. To continue my analogy
it's like saying well if I only speed by no more than XX km/h then I know that my speeding ticket, if I get one, will only be $YY and Z number of demerits.
There is some discussion about whether reverse photoperiod and 24-hour photoperiods really have any effect at all .. I personally have tried both and have noticed zero results with either. YMMV but that's how it worked for me .. (i.e., neither way was a foolproof protection against it).
If you have caulerpa or halimeda (halimeda WILL sporulate just the same as caulerpa BTW), be prepared to live with the risk that the stuff will do it sooner or later. Keep the stuff at bay, then it won't cause devastation. Or use species that are known to not sporulate ... Like this
C. linum spaghetti/green-pubic-hair/brillo-pad algae, or eelgrass/seagrass (if you can ever find a Canadian supplier for this please please please let me know).