Sale of vacation rental property

I sold a vacation rental property in 2019 at a large gain; the property was never a personal residence. The business asset section asks if the business use varied during the years, which it did, and if the answer is yes it says TT can't determine the gain automatically; you must do it manually. I have a complete record of the days rented and the days of personal use. Several questions:

1. Since I have the data I plan to use a weighted average of the rental days to total days (i.e rental days divided by rental days plus personal days) over the years to determine the business use percentage.

2. How do I unlock the protected cells on Form 4797 to change the sales price and cost basis to reflect the business use % determined in step 1?

3. Where do I record the gain related to the personal use since Form 4797 only reflects the sales price and basis related to the business use?

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