Reference Specimen Set is used when you want your collecting decisions to be repeatable. With reference specimen set, you define what you are testing and what outcome changes your plan.
Before starting reference specimen set, choose the smallest area you can work carefully and safely. Define your spacing, your stopping point, and what counts as a meaningful observation. This keeps the method from turning into random wandering.
During reference specimen set, record both positives and negatives. A lack of finds can be just as informative as a hit, because it helps you narrow the productive zone. Skipping negatives is one of the fastest ways to fool yourself.
When you finish reference specimen set, label what you kept and note what you left behind. If you return, you want to repeat the successful parts and avoid repeating the unproductive ones. That is how a collecting method becomes site knowledge.