it's not a seperate program, Taldren actually scripted it into the game itself, you just gotta know how to unlock it. Here's the instructions:
Open the SFC.INI file in the main SFC3 directory.
Add the line writeoutmodelsizfile=1 in the file, in the section labled [3D]
Remove any models from the models folder that you do not wish to size IE Planets, Stock ships.....
Start up your game and go into Single Player Skirmish
When you click on "Start Single Player" button, your game will hesitate. Depending on the speed of you computer and the number of files you have in the models folder, it could take anywhere from a few seconds to a couple of minutes. You game will act locked up, but it's not. Don't close it or it won't work. When the screen changes to the Mission Selector screen, just back out and exit the game. Go to the Models folder in your game, and you'll see a file called Model.siz Open that file in notepad and it'll have every model listed that was in the folder followed by it's size. For whatever reason, it puts decimal points in. The size of 7.78 in the file will be 778 in the DefaultCore. Put the size value in the last column of numbers for the ship(s) you wanted to size, and there ya go. It will size the shields to the proper fit around the ship, and it will adjust the zoom so you can see where you are flying as well.
**Please Note: If you get an error report durring the writing process, when the game is locked up, Don't panic. If you have too many ships in the Models folder, it can't handle it. Just take the file you get, copy it out and rename it. Find out where it left off and remove the files it already sized. It lists the ships in alphebetical order by the name of the folder. Just find out which ship it stoped on and remove all folders before that and run again.
***After you run the program, you can switch the 1 to a 0 on the line you added. That way you'll still have the line if you need it and won't have to go searching for this post. Just switch it back to a 1 to work (0 is turned off, duh)