When to Change a Thought

I’ve been in SCS for about 6 months and am uncertain (trying to avoid the word “confused” :)) about when to change a thought.

I thought I understood the unintentional model, intentional models for desired results and thought ladders. Today I listened to podcasts 286 & 287, Pure Circumstance & Passing Through Neutral and now I’m uncertain about when to try and change my thoughts. For example, I started out wanting to lose weight but I realized my weight wasn’t the problem, loving myself is the problem. So I have the unintentional model, intentional model and the thought ladder.

How do I apply passing through neutral? How long do I sit with the feelings based on the thoughts from the unintentional model before working with the thought ladder? How do I know when to move on?