a couple of my basic guidelines

In case anyone out there might be wondering how I decide on some of my Silhouette and Speed choices I have provided a chart below.
I started by taking the known sizes of all of the published ships, finding the published minimum and maximum length for each Silhouette. Then I played with the numbers until all the ships fit into a nice progression going up to the largest SHIP (i figured i would throw out the statistical outliers like the death star and other ridiculously insanely huge things). the result was the Silhouette  to approximate size (length) chart below.
Obviously this is just a guideline to which there are exceptions. However this guideline helps to keep my decisions as well as the relative representation of ships size, consistent.

Blah blah blah, similar process and result for speed.

Silhouette	Approximate size
0	smaller than person
1	person sized (2 meters)
2	2-4 meters
3	5-20 meters
4	21- 50 meters
5	51-200 meters
6	201-400 meters
7	401-900 meters
8	901-2,000 meters
9	2,001-4,000 meters
10	> 5,001 meters
Speed Rating	Atmospheric Speed
1	1-160 kph
2	161-300 kph
3	301-600 kph
4	601-1000 kph
5	1001-1500 kph
6	1501-2000 kph
7	2001-3600 kph
8	3601-4400 kph
9	4401-5500 kph
10	5501+ kph