Using Small Business reserves is one way to carve out something for small business.  Another way is to determine if it is a consolidated or bundled requirement and how to break out pieces that small businesses can do.  You must do market research to determine what portions of the requirement could be set-aside for small business (either full or partial set-asides).  Let your market research dictate your recommendations.

If this is a follow-on requirement, is a small business the incumbent?  Can that still be done by a small business.

Also, if you are unable to carve out part of the requirement for small business set-asided, what are the subcontracting opportunites for small business?  Your market research will again dictate what could be done by small businesses.

Reach out to your SBA Procurment Center Representative can certainly help you.  You can also discuss ideas with other Small Business Professionas.  Doing market reserch on the requirement and finding small businesses that can do portions of the work will help you achieve your goals.

The DoD OSBP Acquistion Guidebook, https://www.dau.edu/tools/t/DoD-OSBP-Acquisition-Guidebook, may be of some help or other tools on the DAU tools website,  https://www.dau.edu/tools.  Search by the Small Business Programs topic area.