Hi John...
The palette is just like a repository of stored sketches... and you cannot store a sketch without the dimensions. Therefore I would be HIGHLY doubtful you could store something to the palette without dimensions.
Once upon a time I might have suggested turning off Intent Manager, creating the sketch, and storing the geometry BEFORE attempting to regenerate but those options are definitely gone from Wildfire 5. I'm not even sure THAT would've worked.
There is also no way to LOCK the position of sketch dimensions. I know what you mean about these dimensions "moving" around as if they have a mind of their own. All I could suggest is that instead of a complex sketch requiring many dimensions perhaps you could switch to an UDF feature? You could break the feature into smaller sketches and therefore present a cleaner, more user-friendly interface using UDFs. Of course, these have their own downsides.
I wish I had a better solution for you... sounds like you need something like SNAP lines inside a sketch. That's definitely something we don't have yet.
Good luck!
-Brian
