It's easy to find a fbcm than a gcm where i am so i was wondering is it ok or just a pain in the butt to do so?
So, you last said that you had GCM hens.
Based off that you would need to find a BCM rooster that hatched from a darker egg, or from a line with darker eggs.
This isn't really required, but since you are crossing, it's a perfect opportunity to bring in darker eggs. At a minimum at least as dark as your hen's eggs.
First crossing would yield sex links. All males will be single (dark) barred. All females will be black coppers.
Raise the black coppers and have a breeding group with the BCM rooster, or sell them.
Take the nicest single barred rooster and cross to your hens. Female offspring will be half black coppers and half correct golden cuckoos. Male offspring will be half single barred (dark) and half double barred (light).
Take the nicest double barred and breed to your hens and they breed true. All males will be double barred (light) and females will be dark. You can usually sex them at hatch as well. Males will be gray, females black.
You will get different colors of red to gold in the males. I've had some look like black coppers with barring and some light blonde with barring.
It takes some work, but you will have started your own line.