Thinking out loud...
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Average Person Read Aloud Rate: 183 words per minute.
Number of Words for 5 minutes of Audio: 915 words.
Current Writing Speed: Approximately 1,000 words per hour.
Number of Words for 60 minutes of audio: 10,980
Number of Hours to Write 60 minutes of audio: 11 hours
Number of Words for 4 60 minute episodes per month: 43,920
Length of Average Fiction Novel: 50,000 - 125,000 words.
Number of Hours to Write 4 60 minute episodes per month: 44 hours
Required Number of Hours to Write Per Day: 1.57, 7 days a week
Average Number of Hours Needed to Edit and Produce 60 minutes of audio: 1.5 - 2 hours.
Minimum amount of time to record one hour of audio: 1 hour
Per episode time requirements: 11 hours writing + 1 hour recording + 1.5 hours of editing = 13.5 hours per week.
Number of Hours to Write and Fully Produce 4 Episodes per month: 54 hours
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...and that's if everything goes smoothly.
Time to adjust some expectations.