Web design - Length of To, CC and BCC text fields

Any email exchange server supports around 125 email addresses in to, cc and bcc fields. And each email can be of length at the max 256 characters based on RFC 2821/3696.

I am designing a web page to accept email addresses for user notification. Based on the above statements length of these fields has to be set ~ 35000 characters. Which is practically not a convincing.

Would like to know if there are any best practices.