The best way to deal with grout shoulders is to make sure you minimize the chances of cracking before you start. There are 5 things you should consider before you proceed with the placement of your grout.
1. Design
Make sure you choose a design that is less prone to cracking. Minimize the size of the shoulders while still making it easy from a constructability standpoint. Think about how the grout will have to be placed and design access in your base plate or frame to make application and air evacuation easy.
2. Product Selection
Choose a product that will flow and fill your entire space between your base plate and the foundation. Visualize the flow and how it will move air from around the back-side of obstacles like shims and anchor bolts.
3. Preparation
Make