Wings since this was your first time doing the whole theme thing would you like to share your immortal technique? I am just about as careful as you sounded and I would like to get it right too! I don't think I will have access to adb so if that's what you used then share for those who might come across this thread....
Im just now messing with the sdk package so no you dont need that at all. Step by step what I did is:
1. I already had the official sprint cl14 install so I skipped the first set of instructions on that. If you dont have the cl14 you need to do that first.
2. Download the sprint update tool from here
Sprint Software Downloads - Smartphones - Samsung Moment with Google
3. Install it on your pc
4. On your pc navigate to C:\Program Files (x86)\Samsung Electronics\SWU Upgrade\Models\Binary\
5. Cut the sprint file labeled SPH-M900_CL14_MR.tar and paste it somewhere for safe keeping in case you wanna go back to stock
6. Download zefies 14.3 from here
MEGAUPLOAD - The leading online storage and file delivery service
7. Extract the file in the tar and paste it into the folder you just removed the stock file from (C:\Program Files (x86)\Samsung Electronics\SWU Upgrade\Models\Binary\)
8. Power off your phone and remove the sd card
9. Run the sprint update utility you downloaded first without your phone connected to the pc. and follow the instructions on-screen exactly
10. Once the update completes and loads the OS remove the battery on your phone and reinsert your sd card.
12. Restart your phone.
To install a new theme follow these steps.
1. Download the cl14 theme template located here
http://samsungmoment.googlecode.com/files/cl14_theme_template.zip
2. Download the theme you want to install from the sdx forums theme section located here
Theme files
3. connect your phone to your pc and load those 2 files into the root directory of your sd card
4. Turn off your phone
5. hold down Volume+Talk+End until the recovery screen appears.
6. Select Data
7. select Clear dalvik cache
8. Select Apply any zip from SD and select CL14_theme_template.zip
9. Once that completes select "Reboot"
10. Once your phone is fully booted back up. Power off your phone back off and boot into the Recovery Mode again (Volume+Talk+End)
11. select Clear dalvik cache again
12. Select Apply any zip from SD and select your new theme.zip
13. Once again, select Reboot system now
It can take up to 5 minutes for your phone to reboot the first time so be patient. You also will have to reload any widgets you have on your screens.
As a side note, I used the black aero theme and apparently there's an issue with the launcher file so the default home screen (the 3 screens) will not work. You need to be running a 3rd party home app like panda, gde, open home etc and have it as your default home screen or you will just get a black screen. From what I read not all themes have this issue. Gator boots theme for example works fine.
That's about as detailed as I can get so I hope it helps.