James,
Your method of attachment is fine. Some people attache from the back first but I believe that your method of going from the front to the back makes for a better alignment and starting point. You can position the hair line exactly where you'd like it and then work the back down. I don't know if a butter knife is necessary but if you're comfortable with that then fine. Just keep doing it the way your are--it's fine.
Regards,
John