bore sizes for aftermarket calipers

[Ram85SPG]

Hi All,
I'm getting ready to pull the trigger on some aftermarket brakes for my 85 spg. I am planning to go with the Powelite calipers from rallydesign.co.uk using Luke's adapters, with 1" bores, and NDL Dynalites up front. I wanted to get an opinion about the best bore size to match the stock brake bias. Should I go with 1.75" or 1.62"? If my math is right 1.75" gives 3/1 bias in the front, whereas 1.62" bore size would give 2.6/1; I just compared the swept area of the pistons front to back.

Now the stock bore sizes are 54mm and 30mm for front and rear respectively, which gives 3.2/1, so that suggests that the 1.75" is closer to stock. Can someone comment on how different the differences in bias would be in practice? I am going to use the stock brake booster and master cylinder (or if I need more volume I might upgrade the MC to a 1" wilwood unit that fits the stock brake booster bolting pattern). Thanks!

Ram