CMA minerals appraiser exam — coming from O&G land work, what gaps should I expect?

I've spent 12 years in oil and gas land work — division orders, title review, lease negotiations — and I'm pursuing the Certified Minerals Appraiser designation. I figured my background would cover most of the content, but after 3 weeks of study materials I'm realizing the valuation methodology sections require knowledge I just don't have from my day job.

The income approach and discounted cash flow modeling covered in the exam is more rigorous than the informal valuation estimates I've done for lease negotiations. The reserve categorization questions — proved developed producing, proved undeveloped, probable, possible — I know conceptually but the exam seems to want a lot of precision on SEC definitions and PRMS standards.

I'm about 5 weeks into studying, roughly 90 minutes a day, and my practice exam scores are 68 to 72%. That's not where I want to be with my exam date 4 weeks out. The sections on comparable sales analysis and market approach for mineral rights are the most unfamiliar since I've mainly worked the production side of transactions.

For people with a land or O&G background who've gone through this exam — how long did it take you, and were there specific resources that filled the appraisal methodology gaps?