I would suggest the following books for your preparation towards JNCIE-SEC.
- Day One: Deploying SRX Series Services Gateways
- Day One: Scaling Beyond a Single Juniper SRX in the Data Center
- Learning Bytes: various
I didn’t read any workbook from iNET Zero/Proteus or Twine, so I can’t suggest them. But maybe you have some experience with them and leave comment! Do you know more good sources of informations for JNCIE-SEC?