My only advice is to be patient, breeding chondros isn't impossible it just take time to learn the animals.

I personally would, keep them with DTT's of 87 (stat setting) and offer NTT's 75 (stat setting), and introduce and separate them every so often.

This will allow you a to use the male as your indicator.
You'll know when the female is receptive, because he'll be on her like white on rice.

Hope that helps!
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Greg Stephens
Arboreal Specialties
gstephens1@zoominternet.net