1A in .300 British Sight Height

[xl883lo]

Trying to determine the "sight height" (distance between the centerline of the bore to the centerline of the scope) to order a Leupold CDS custom turret. I have measured it as the following:

1/2 breech diameter = 0.23"
Top of breech to top of rib = 0.60"
Medium ring height = 0.46"
1/2 scope diameter = 0.50"
TOTAL = 1.79"

I measured the top of breech to the top of rib the best I could with a set of calipers, but I am not completely comfortable with the results. Any comments or does anyone have any more reliable measurements?

Thanks