Just so that you girls are aware, a reptile becoming picky can be a sign of problems. I don't think this is the situation with your gekos. I just want to inform you so that you do not miss early signs of illness. Something to read. As you can tell typing is too much work sometimes.
Reptile Health: Knowing What is Normal - Page 1
Other things to consider when offering prey:
Has the gecko had time to digest the large meal from the day before.
Can the gecko see the insect.
Is it intimidating due to large size.
Sometimes after handling they can feel to stressed to eat.
Did you dust with a MVI which some will refuse.
Time of the day. "Why are you waking me up? It's not dinner time yet!"
Try to offer food when they are on the warm side of the enclosure. I had a friend call me once freaking out." Micky does not want to eat!" I asked if it was the first time and she said yes. I noticed she called me at 5pm. I told her to observe Micky to make sure she had warmed up. She calls me back laughing and informed me that a few minutes after Micky moved to the warm side, she started eating. Well the gecko was sleeping on the cool side and so she was not going to have much of an appetite.