If you’re going to use a DSLR for recording the ceremony, I would definitely recommend an AC Power Adapter like this one to run the camera for longer than a single battery could keep your camera going: https://www.amazon.com/gp/product/B003XN37YW/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
I just started using one of these for my webinars that run for over an hour, and haven’t had any problems with my Canon 7D Mark II overheating.