Find the Garrett housing nick, I bet the puck covers the hole in the Garrett housing.
Or just weld up the hole in the turbo you have and redrill
Did someone run a external gate on your 6152 and that's why the hole B so big?
Years ago I made my own 1/4 inch plate and drilled a 3/4 pick hole because the thdp wouldn't cover it 100%
Cutting up the new pipe for a new puck seems a little extreme....
Did you ever call RJC to see if he had the new plate and you drill the hole?