Jumping in here because wedding shoots are no joke! The 5D IV is an absolute beast but you really gotta maximize those dual slots if you want that fast storage you mentioned. Seriously, dont rely on the SD slot for speed... it is capped at UHS-I. You need a high-speed CF card for the heavy lifting. I totally recommend the SanDisk 128GB Extreme PRO CompactFlash Card 160MB/s. It keeps the buffer clear when you are firing off bursts during the ceremony or the first dance. It makes such a massive difference! Since you want to stay lightweight and skip the grip, look at the BlackRapid Sport Breathe Camera Strap instead. It sits across your shoulder and keeps the weight off your neck, which is life-saving for those long Seattle wedding days. It is way more low-profile than a grip but feels so much more secure than the stock strap. Also, grab a Lexar Professional 1066x 128GB CompactFlash Card as your secondary. Having two fast CF cards is way better than using a slow SD card that will just bottleneck your camera while things are getting busy. Staying light is the way to go and these items wont add any real bulk to your setup. You are gonna have a blast, that camera is fantastic!

Honestly, skip that bulky grip if you want to stay light. Ive been using the 5D IV for years and im super happy with the handling without it. Since you are doing weddings, you definitely need more juice. I would grab two or three Canon LP-E6NH Rechargeable Lithium-Ion Battery packs. They have worked well for me and last longer than the older versions. For storage, dont skimp. I use the SanDisk Extreme Pro 128GB CompactFlash Card 160MB/s because it keeps up with the buffer during the ceremony. Use the rest of your cash on a Peak Design Slide Camera Strap. It makes the heavy body feel way lighter on your neck after 8 hours. Tbh, you will be much more satisfied with a good strap than a grip that just adds weight.

Following this thread

Regarding what #3 said about "Following this thread"

• I have been shooting weddings for years and I honestly think people overcomplicate the storage thing while ignoring actual comfort and safety. 1. I'm gonna disagree with the idea that more batteries are automatically more important than a better strap. If your neck is killing you halfway through the reception, your shots are gonna suffer. Just get a decent shoulder strap from BlackRapid or Op/Tech USA and your back will thank you. 2. Everyone is talking about speed but reliability is the real king for weddings. Just buy any professional grade cards from ProGrade Digital or Lexar and make sure you're writing to both slots simultaneously. You really dont need the absolute fastest models on the market for most wedding work, just consistency. 3. Since you are in Seattle, please just get a rain cover. Ive seen so many people regret skipping this. Just grab any protective sleeve from Think Tank Photo or Ruggard. Basically, focus on what keeps you shooting longer without pain or gear failure... the rest is just noise.