Send a specific set of string from the LB

Are you simply trying to verify that the server will successfully use a specific cipher?

Member Boneyard has an example in this post. Use openssl with the s_client and -cipher argument. This command would be run from a bash shell.

If you want to verify the list of ciphers that a server will support (other than verifying config of server itself), a web search for something similar to 'openssl test server cipher' will return several Stack Exchange and other posts with bash scripts to loop through and identify server-side ciphers.