Hey Aaron,
There are many backend Actions being processed on the Estimate screen. I would start by looking at the OnScreenLoad actions and then head over to the hidden object on screen: 'OnPopUp-Apperance-DONOTSHOW'
I'm not sure if you are starting from a new screen, if so - would an option of copying the Estimate screen and customizing that by removing/hiding the extra fields you do not need maybe a better route?
- Mortaza