Must say that I would at least ask the question as to whether a 24hr FARS is of much benefit in a location like St Johns?
I'm guessing that there's not a huge amount of bright sunshine, especially in the winter months, which (a) limits the usefulness of the 24hr FARS and (b) means that the batteries may be more likely to go flat, then the fan obviously stops and ventilation of the shield actually becomes worse than with the standard passive shield (because of the much more enclosed shield design). But at the same time there is probably at least some wind much of the time to help ventilate the passive shield naturally.
In these respects it's similar to the UK and my advice here is either to stick with the passive shield or if you definitely do want a FARS then to go with the daytime-only FARS add-on kit which retains much of the standard passive shield.