A straight reamer taper from, 13.20mm down to 5.20mm over 345mm will give as good as any taper,to start with,for a concert D chanter bore, the tone holes will then have to be worked out and drilled to size to bring the chanter into tune with its self,but with any chanter being copied,you need a good one to start with,its no good copying Shi—, 
you also need to know how to make a reamer,with a perfect straight edge, I didnt say it was easy,but I have done a lot of home work,and I know what will work and give a reasonable fished chanter without having to under cut and use rushes to get the instrument in to tune. 
then the chanter has to be reeded up,and from then, the chanter is only as good as the reed in it. 