In the piano, we made 1 and 88 leveling samples first (where case parts are at hand to consult) and then turned up their Keysteps to make them bedding samples as well. Pre-setting the height for those two keys means that when leveling is done, they will already match the rest of the keys and not need touching up. Convenience and efficiency. Two good reasons for setting these samples in the piano and two good reasons for taking them to the bench to level the keys. There, enjoy better light. A better height. Easier access. And no need to shift the action out of the piano, punchings precariously perched on the keys, for insertion.
Setup now complete, record the hammer spacing scale and template heights at strike. The hammer spacing scale comes from the spacing of strings along the strike line as hammers must align with their strings. Whatever traveling, squaring, or spacing we receive in a worn action, hammer wearmarks show where their strings are at strike. So don't touch their traveling, squaring, or spacing (and don't file them) until you record the center of each unison on the Regulating Rack at strike. This will provide a real place to return to as things are changed during the regulation.