Hi Smylee, I think 3 keys and 2 pipes on a 30to 32 inch bbl is appropriate. I went to PA to look at the Turvey rifle and I’ll try to find the photos for you. If I had to do it over I would use keys instead of pins for the simple fact is they look cool and easy to drop the bbl to clean.
BTW my rifle is a Jim Chambers Kit.
Cheers Richard