hi the number of lines is not so relevant because the same lenght of episode (reading time) can have really different amout of coding based on how much it is advanced and how much choices and branching the story has.
The only thing relevat to reader is reading time - the minimum is around 10 minutes - if it is less you will get lot readers complain that they havent got enoug for one pass.
The most common is 10-15. Some do longer but again if it is too long some readers surprisingly do not like that too so 10-20 is the amount where \ou will get minimum complains about the lenght.
Simply use stop wantch and read your story like if you are regular reader if you have 10 and more minutes ou are fine.