A thought:
Unbeknownst to me, one of my fishkeeping behaviors resulted in transporting eggs from main tank into shrimp tank. Said behavior consisted of taking clumps of greenery from main tank and putting it into shrimp tank for feeding and "tidying up."
One day while studying the shrimp tank, lo and behold I spied a fry! After that I watched the main tank closely and as soon as I saw a fry I would transfer it into the shrimp tank.
I'm not sure exactly how many fry resulted from the transport of greenery containing eggs, but I do know that my shrimp tank became a very successful grow out tank.
I admit my knowledge is scant regarding the fish you are going to breed but is it possible that, once you think that eggs exist, you might transfer the nest and surrounding greenery into a grow out tank?
Here is a video of my red cherry shrimp tank where you can see some WCMM fry in the foreground and several little pair of blue eyes in the background.
(If I'm not mistaken I think earlier in the thread someone may have mentioned just moving the whole nest at a time, which is essentially what I'm suggesting).