CCA CMMC assessor exam - is it worth pursuing before the regulation fully stabilizes?

I've been doing IT security consulting for about 8 years and my firm is starting to see a lot more DoD supply chain clients asking about CMMC. I'm looking at the CCA certification and trying to figure out if the time investment makes sense right now or if I should wait until the regulation settles a bit more.

From what I've gathered, the CCA exam covers cybersecurity fundamentals, CMMC-specific assessment methodology, and the 110 practices across the 17 domains. The exam is 75 questions and you need a 70% to pass. I've been working through the CMMC Assessment Process document and the NIST 800-171 controls and there's a lot of overlap with my existing CISSP knowledge but framed differently.

My concern is the authorized C3PAO pathway requirement. Even after passing the CCA exam, you need to complete a certain number of assessment days with a C3PAO to get fully credentialed. Finding a C3PAO willing to bring on a new assessor for that experience time is apparently harder than the exam itself.

Is the exam format mostly multiple choice or are there scenario-based questions? And for people who've already passed, how much did prior NIST 800-171 or FedRAMP experience actually help?