I designed this spool specifically for the Laywoo-D3 filaments. This one is actually printed in the Laywoo-D3 filament. Its a little bendy, and I suggest printing in either ABS or PLA.
I also designed this to be printable on an UP printer (140x140mm) and with no support.
Centre hub is 30mm in diameter. And the arms are adjustable to suit either 1.75mm or 3mm.
The STL can be downloaded here