First, ACX pays monthly, just like KDP and CS. The pay 30 days after the month of sales. In other words, whatever audio sales I have in March will be paid at the end of April.
There are a number of payment amounts. depending on if the buyer is an Audible subscriber or not. I sell between 10 and 20 per day usually and my average royalty per sale is $2.88 currently.
To determine if royalty share is a good fit for you, do the math backwards. A good narrator will cost at least $200 per finished hour. ACX uses 9400 words per hour as the average. This will give you a good baseline for straight pay to the narrator. A 94K word book will be about ten hours long and cost about $2000.
So where's the break even for the narrator for this 94K book with Royalty Share? It's a seven year contract. If you average $2.88 royalty per sale, as I do, the narrator will get $1.44 of that. 2000 divided by 1.44 equals 1389 sales for the narrator to earn the same money. Seven years X 365 days equals 2555 days in the contract. 1389 sales divided by 2555 days equals .54 sales per day, or one sale every other day.
If you sell more than one audiobook every other day, the narrator comes out ahead with Royalty Share. And you come out behind. I don't know about you, but I wouldn't even consider doing it, if my goal was to sell only one audiobook every other day.
To put a better slant on it, consider if you sold two audiobooks per day. The narrator will earn $2.88 every day and so will you. In the lifetime of the contract (2555 days), the narrator will earn $7358.40, or $5358.40 more than had you just ponied up the cash up front. Four sales per day? You pay the narrator over $12K instead of $2K.
Yes, it's an expensive investment. But way too much money is left on the table with Royalty Share.