I can't find it now, but when i purchased my harken 57mm Ratchamatic Blocks (6 years ago?), they mentioned a minimum operating range (or similar name) and it was close to 12". I can't find that data on their site anymore
When measuring mast rake, does the main have to be hoisted and tensioned with the down-haul? I am thinking the mast bends, but maybe not enough to care. The measurement I have seen is to use the main halyard to compare the mast top to bow with the mast top to stern. 16 inches is recommended in some places. Does anyone have other measures?