So you mean that the red thing in the bgk's tail is a sign that its ready to lay eggs, you sure. You should at least provide pics before saying such things. I don't even know if your telling the truth or not.
Keeping the fry alive will be a challenge. They are extremely sensitive.
Don't feel bad if you have high losses - they are just not very hardy when that small.
I am looking for a mate for my BGK to try the same thing.
Please keep us posted.