From my own experience, steel yourself for the wedding couple and their relatives being underwhelmed with your photos because they are rather grainy and not in colour.
I went down this route with Delta 3200, determined to use what little light there was in the venue. I knew there would be many digital cameras and phones there to get colour shots using flash, and like you I wanted to do something different. I had previously gotten very nice results with Delta 3200 at box speed in Emofin, so I gave every shot 1/30 at f/2 and developed as before.
All my shots were under-exposed, I disliked them all anyway, and the couple made no comment when they received them. This below was arguably the best of the bunch, and only because the cake was rock hard!
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