http://www.oocities.org/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