I make no statements and have no opinion about how many British people drop their terminal gs; but in West Texas in the 70s, this was seriously given to me, more than once, as the reason why people thought I might be from England. It didn't make any sense to me then, either.
I've tried it out loud several times, and it seems I alternate between putting the primary stress on the first syllable and the secondary stress on the second syllable, and vice versa. The third syllable is consistently unstressed. Inconsistency in the stress placement is probably a result of my aforementioned hybrid accent. The chief hallmark of the West Texas accent is to place the primary emphasis squarely on the first syllable of most multisyllabic words regardless; the result, for me, is that I tend to distrust this emphasis and stress the second syllable. But in this word, the primary meaning is in the first syllable, and stressing the meaningful syllable makes the most sense.
If people understand you when you say it, that's the main thing. It's not a word I say aloud often, anyway.