If you don't want to use tweakUI or find it doesn't work, here is the manual method:
1. Set up the screensaver as you want under your login.
2. run regedit & locate the following key:
'HKEY_CURRENT_USER\Software\Microsoft\ScreenSavers\Text3D'
3. With the 'Text3D' key highlighted, choose File -> Export and save the file wherever you wish.
4. Right-click the file & open it for editing. It will look something like this:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\ScreenSavers\Text3D]
"AllScreensSame"=dword:00000000
"SurfaceType"=dword:00000001
"Specular"=dword:00000001
"SurfaceColor"=dword:00777777
"CustomTexture"=""
"CustomEnvironment"="C:\\WINDOWS\\Metal Links.bmp"
"UseCustomColor"=dword:00000000
"UseCustomTexture"=dword:00000000
"UseCustomEnvironment"=dword:00000001
"MeshQuality"=dword:000001f4
"Size"=dword:0000000a
"RotationSpeed"=dword:0000000a
"RotationStyle"=dword:00000001
"DisplayString"="Hello World"
"DisplayTime"=dword:00000000
"FontWeight"=dword:00000000
"FontHeight"=dword:00000060
"FontItalic"=dword:01000000
"FontCharSet"=dword:00000001
"FontPitchFamily"=dword:61005400
"FontFace"="Tahoma"
[HKEY_CURRENT_USER\Software\Microsoft\ScreenSavers\Text3D\Screen 1]
"Leave Black"=dword:00000000
"Disable Hardware"=dword:00000000
"Width"=dword:00000000
"Height"=dword:00000000
"Format"=dword:00000000
"Adapter ID"=hex:3e,1e,b7,d7,50,42,cf,11,61,7f,05,21,10,c2,cb,35
5. Replace all occurrences of 'HKEY_CURRENT_USER' with 'HKEY_USERS\.DEFAULT'
6. Save the file & then import it into the registry.
Keith