I mentioned in my previous post that no matter where you end up in terms of presenting your audition repertoire, you need to stage it out in preparation for your auditions.
A simple test you can give yourself to prove this: Think about the comfort level you have in presenting arias in audition that come from operas where you have either performed the complete role, or scenes from that opera that contain that aria. I think you will agree that when you sing those arias, you feel more physically connected than you do with arias where you have not done this.
The way to create the same effect for those arias that you have not performed on stage, is to stage them completely, either with a coach/director, or perhaps in a swap with a colleague where you do the same for them. After staging the aria, you will find that you will keep elements of the staging for the "audition version" of it, but perhaps more importantly, you will have locked in mental intent, which will allow your body energy to be connected to your voice.
In addition to allowing you to feel more comfortable in the audition, you will also undoubtedly sing better because of this connection.