Just had a yarn with A G, and he has filled me in on how much work he puts in to such developments, referencing QuikLoad, tightening tolerances, load development, range testing. He indicated that of you wish to contact him directly he can go into details far better than I.
If you wish , contact him directly, he has given the OK for me to pass that on.
Going through and old thread I see you mentioned having a William Douglas double in 470NE for sale. Just touching base to see if you sold the rifle, or if it was still for sale?