Rules based attack sha256

Hi i'm new with hashcat and i started studying how this program works a few days ago, i've read about the brute force attack and i would like to use it in combination with a rules based attack. 
Let's say i've the sha256 hashes of some string that have this pattern: n-_ _ _ _ _ _ _ _ _ _ _ _  (12 alphanumeric values).
I know that this is a very long string to brute force considering that i have 62^12 combination. 
I've noticed a very frequent pattern in the creation of this 12 values string and the pattern is this one:
- at least two number 
- at least two vocal
- at least four capital letter
Using this three condition the number of combinations possible reduce drastically, how can i implement this condition in hashcat ? 
Will the insertion of this condition reduce the hash/s rate ?
Let me know.
Valerio.