http://www.geocities.com/pentapod2300/nam2/xreflect.htm
The table on page 10 of NAM does not go high enough, if you are making really large spacecraft ( most likely cargo/colonial vessels) or small space stations.
Here is a handy table for Reflected Signatures greater than 15, which extends the table found on page 10 of GDW's ( now FFE's) NAM.
REFLECTED SIGNATURE Fixture Points Signature 4,912 16 5,831 17 6,858 18 7,999 19 9,260 20 10,647 21 12,166 22 13,823 23 15,624 24 17,575 25 19,682 26 21,951 27 24,388 28 26,999 29 29,790 30 32,767 31 35,936 32 39,303 33 42,874 34 46,655 35