Reclass to 35G with interim clearance while TS paperwork processes?

I have a question regarding reclass to 35G and interim clearances. I was assigned to an MI battalion as a 91B , which is overstrength and asked if it were possible to reclass to any open MI slots. They said it was possible to reclass to 35G given the proper sign offs. I currently have a secret and submitted my SF86 and all other paperwork for TS but I know they are serverly delayed getting through clearances. I was wondering if it were possible to attend the class with an interim clearance or would I have to wait for the TS to clear. If possible to attend with interim, would I contact my BN security manager for an interim, or who would I contact for the interim clearance. Thanks for any info.