I have a doubt regarding the choice of a potential tool to try tuning the piano (with grace and great lightness); I notice that the most common sizes are the first (small) and the second. The piano in question is a Petrof 114, the measurements taken on the anvil are 5.5 - 6.5mm near the string. In your opinion, what could be the correct choice?
I have a curiosity, if I may ask. How do the measurement numbers differ? I haven't found technical drawings of the keys, nor specific indications regarding dimensions; the only site that reported anything was Chinese, however rather doubtful. Specifically, the first measurement showed a depth of only 10mm, while the others appeared deeper but without indicating the sections.