For 300ssh regarding 1/2" max tuck what is reason under Part F in the rule and how was the 5" determined ?
Maybe for preventing excessive rear lift resulting in erratic handling?
"Item F. Also, the leading edge of the gear foot(nose cone) may not be closer than 5 to the trailing edge of the bottom of the boat".
.......Those are 'safety' rules. The idea is to limit radical set-up's leading to accidents and to maintain a level playing field for all.
Similar rules on max tuck are due in all Stock classes for safety reasons.
Although not clear I assume if tuck is less than 1/2" or zero the gear case nose can be closer than 5" to bottom rear trail edge?