Lenovo ZUK Z2 backplate replacement

The Lenovo ZUK Z2 is a great phone. The backplate is made out of glass and after shattering the back cover 3 times, I thought it was time for a platic upgrade. I've tried to model the back cover as close as possible. The first print in pink fitted after some trimming with scissors.
I decided to play around with changing the filament mid print. I've punched out a Bruce Lee stencil. The depth should only affect the bottom layer. After the first layer, I switched colour and resumed printing. Resul