Once you have the pattern, we can tell you how much to reduce or enlarge it. Without knowing what size you are starting with--there is no way to tell you how much it needs to be reduced or enlarged.
For 6" finished blocks--you would enlarge 133%.
For 10" blocks--you would reduce by 20% or 80% of original--it depends on how your scanner works. Probably 80% of original.
For a 12" block--you would reduce 67% of original
The formula is: 8 (inches) divided by x (x = the size of the pattern you want to change) = x.xx which you would then convert to percentages by moving the decimal point 2 places to the right.
You have a 10 inch (finished) size pattern you want to change to 8". 8 divided by 10 = .80 Move the decimal point 2 places to the right = 80%.
This works for enlarging or reducing templates and paper-piecing foundations WITHOUT the seam allowance. You have to take it off and put it back on if your pattern has it.
Post your patterns as you find them and I'm sure someone will hop on and help figure it out for you.