Hi White Noise..... yeah just 5% would do you for now ... I got that amount when I decided to try adding in grey ...it was hardly noticeable which is what you need as a starting-point..you can increase it a bit on subsequent orders so people don`t see this ` stark` difference in your hair.
My nape hair was like rats tails so it wasn`t an option for me to keep any of it ---if yours is ok that will help give a nice ` finish` at the back..... you most likely won`t need to keep much ` length` there ....just be careful of not having your perimeter too ` high` up or you`ll defeat the purpose as the system hair will not ` lie-in` as well as you`d need it to .... I`d keep no more than about half an inch of your own hair and have the perimeter ` sitting` immediately on the line where the hair has been shaved to.... that way you`ll have no more than half an inch of system hair lying over the growing hair ...that will work best .....if you keep too much ` length` of real hair , your perimeter will be too high up on the back of your head......
It`s great to have the ` luxury` of a nightly detach.... I too prefer to sleep with it off my head... it saves wear on the system too ..... it can be done pretty quickly once you get into the swing of it .... have you sent off the template yet ? If not, you might want to add a little material at the back there ..... I`m sure you`re pretty clued-in anyway, having been wearing toppers up to now .....you`ll know what will work...... I had mine a bit ` high` before and as you said, once you incline the head forward you can feel the hair standing out.... I brought the edge down a lot lower since then.... I keep the hair -length there pretty short --that way it tends to stay ` in place`.