I've looked at several guides, and all seem to be different on stat weighing. This is of course assuming you're hit capped.
The guide on here says:
I'm so confused on what to do. On a side note, what would be the best OS for demo, that won't be affected by not reforging? I.E, demo gear for destro or affl and not being too affected.
All of demo's stat weights are very, very close and depend on your gear. That being said I'm personally of the opinion that it's pretty much a wash and you could easily just decide your reforgings based off of your second spec's priorities.