Over the long-term, you want to grow the number of your above-average customers so they make up a larger part of your customer base.
You should absolutely continue to grow your customer base as a whole through customer acquisition. You just want to accumulate more above-average customers as you go.
There is no best number of above-average customers. What is best for one store might not apply to another.
Ideally you want it high and to be growing over-time. A good segmenting system like Repeat Customer Insights should keep track of it month by month for you.
Eric Davis
Segment your customers to find the diamonds in the rough
Not all customers are equal but it is difficult to dig through all of your data to find the best customers.
Repeat Customer Insights will automatically analyze your Shopify customers to find the best ones. With over 150 segments applied automatically, it gives your store the analytics power of the big stores but without requiring a data scientist on staff.