Well, it's been a few days so the beta request totals have changed
As to your question, CJ, for me the answer is: As many as it takes to figure out what's a note based on personal taste and what's a note that people are in agreement over. Now, personal taste is not meant to be dismissed out of hand, but when multiple betas say something, it's time to sit up and take notice. On the other hand, too many beta notes can certainly get overwhelming, so there's a balance to be had there. Plus, if you need a second round (or especially for those who are looking for alphas, of which I suggest you only get one or two), it's better not to burn through all the fresh eyes who might be interested in your novel, so having 10 people look at it now will probably limit how many people might be look at a new draft with fresh eyes, if you need them to (not every revision requires this). But another thing to keep in mind is that sometimes betas just can't finish their read/notes for you, so the number you start out with might not reflect the number of notes you end up with.
Just all things to keep in mind.
As to your question, CJ, for me the answer is: As many as it takes to figure out what's a note based on personal taste and what's a note that people are in agreement over. Now, personal taste is not meant to be dismissed out of hand, but when multiple betas say something, it's time to sit up and take notice. On the other hand, too many beta notes can certainly get overwhelming, so there's a balance to be had there. Plus, if you need a second round (or especially for those who are looking for alphas, of which I suggest you only get one or two), it's better not to burn through all the fresh eyes who might be interested in your novel, so having 10 people look at it now will probably limit how many people might be look at a new draft with fresh eyes, if you need them to (not every revision requires this). But another thing to keep in mind is that sometimes betas just can't finish their read/notes for you, so the number you start out with might not reflect the number of notes you end up with.
Just all things to keep in mind.