Congrats on the a7R VI! Those 61MP files are total monsters and will eat your storage for breakfast, no joke. I have been shooting Sony bodies for years and went through the exact same stress when Type A cards first launched. In my experience, you definitely pay a Sony tax for the name. They are solid, but for a 400ish budget, getting two is gonna be tough. Here is the breakdown based on what I have used over the years:

• Sony TOUGH CFexpress Type A 160GB: These are basically the gold standard for pure ruggedness. I have never had one fail on me, but the price per GB is just brutal. If the client is super high-end and you are paranoid, maybe they are worth the peace of mind, but you will blow your budget.
• ProGrade Digital CFexpress Type A Gold 160GB: These are usually my go-to recommendation. I have been using a pair for a year now and they have been rock solid. I know people talk about firmware stuff online, but honestly, I havent seen it personally. They run much cooler than the Lexars too.
• Lexar Professional Gold CFexpress Type A 160GB: I tried these and they are fast, but yeah, they do get pretty toasty during long bursts. If you are doing heavy commercial work, the heat might make you a bit twitchy tho. Honestly, I would just grab two of the ProGrade cards. You wont notice a speed difference in the field compared to Sony, and you stay under that 400 mark while still having your redundancy. Good luck with the gig, Seattle is a blast to shoot in!

To add to the point above: honestly, I went through the exact same freak-out when I first saw those file sizes on my rig! It is totally wild how fast they fill up and the buffer lag is no joke when you are in the zone. I remember shooting a high-speed sequence last year and my cards just choked... it was so embarrassing! I felt like I was stuck in slow motion while the action was happening right in front of me. Anyway, I spent way too much time researching this because I refused to pay the Sony tax if I didnt have to. Here is what I found works amazing:

• ProGrade Digital CFexpress Type A Cobalt 160GB: These are absolute powerhouses! I have used them for huge sessions and they never get hot. They are VPG200 rated so the sustained write speed is super consistent, which is exactly what you need for those 61MP files. Honestly love these.
• Exascend Essential CFexpress Type A 180GB: This was such a fantastic find for me. You get that extra 20GB over the standard 160GB cards which actually adds up when you are shooting uncompressed raw. Super reliable and way more budget friendly than the big names.
• Pergear CFexpress Type A 260GB: If you want to stretch your budget to the max, these are incredible! The capacity is just nuts for the price point and they have held up great for me. Seriously, dont stress too much about the brand name. As long as you go with a card that has a solid VPG rating, you are gonna be totally fine for your Seattle gig. You got this!!