I think you are making this way more complicated than you need to make it.
1. You should not need to use Inspector to edit the values for controls. Inspector is generally used to edit the properties of a control, you know things like size, color, shape, and type. The values for the controls are stored in the default preset which is loaded when you start up the emulator, deploy the project, or the role starts on the NION.
2. I do not ever recommend going in and actually editing anything in the design.xml file. It is a bad idea, just don't do it.
It sounds like you want to adjust the default values for some controls in your project. This should be considerably easier to do than it sounds like you have been making it. You should be able to emulate the project on your computer and modify the settings of the desired controls. Then, go to File > Settings and choose Save Default Settings. Now, when you start it up next time your new default settings should be present.
If you are trying to adjust the appearance of some blocks or controls, then you should be editing the properties of those objects directly and again not using Inspector or editing design.xml. The easy way (and I am all about doing things the easy way) is to right click on the object you wish to edit, select either Device properties or Graphic properties (it depends on if you are selecting a control or a label, only one will show up in the right click menu), then use the dialog box to set up the control or graphics the way you want them to be on the screen. Save the project, emulate or deploy the project, and you should be good to go.
Please remember, there are plenty of complex things you can do with the system, there is no need to make it more complicated than necessary.
Burnt Orange Studios