Closed SID board or layout for C16 PLUS 4 w/o SID-IC

I only have a handrawn schematic.
With the minimum of an Eagle file or alike I could possibly have produced a PCB to build an old dream of mine: SID-sound in my PLUS 4.
I am just rather inexperienced in circuit design .... I know which end to hold of a solder iron, that's it.
No SID-IC needed.

I have this one:
http://plus4world.powweb.com/hardware/NSTs_Audio_Extension_V2_0
I think I bought the last one. I guess you could ask them if they'd give you an Eagle file for it.

Good advise. The Hungarian developer has quickly answered my enquiry. There will be a new batch in the course of the near future if I interpret him correctly.