Is there a better model

Nice work

Actually thought you were using the 'insert premeasured filaments' method, until i looked closely at the machine

If you want to make models yourself, I see a combine-multiple-stl-file entry in slic3rs menu, looks like that can make a multi-material .amf file. So if you know how to design things presumably you can make .amf files.

I will not do the model,Hope to be able to recommend a few amf website