Any method that you would normally use to make body repairs… yes… Bondo would work if properly applied is suitable for large dents if you want the best end result. Our bedliner and other coatings which consist of 3 parts include a powdered component which allows you to control the consistency. You can also mix a small portion with enough powder to trowel apply for smaller dents or irregularities.
You should always give any filler whatever the recommended time is based on the product instructions to cure before coating with any product. If using the SL&C DIY kit materials, allowing full cure is not required before applying the final product.