Hey Jarvie I can answer these,
#1
30x was taken from 2 sales of gold foils a chromatic dragon 350SBD and a selenia sky 450SBD I found the correlation that selenia sky averages 15SBD right meow and a dragon around 12 SBD and so those numbers created 15x30=450 and 12x30=360 pretty much lining up for both of them and I used average values for cards after that to try and reverse engineer it, never precise and the market will dictate but in these beginning stages we work for some semblance of averages.
#2
I spoke with calumam and that posting was in error, you are correct the number is 1% and will be corrected and also correct that from day to day that number has been fluctuating and sometimes goes below 1%
#3
drop rates for foils was determined by taking the regular drop rates for types and determining 2% of that which gives you averages on drop rates for different types :)