Taking your 3/4 point. Statistics produced by CONGU (and reinforced by figures from the USGA) show that on 3/4 difference the low h'capper will win 61% of the time. When full difference is used this falls to 55%. I have just analysed our KO comps and off 3/4, 68 of the 89 matches played were won by the lower h'cap player. The committee have now decided that next year the full difference will apply.
This is mandatory in Scotland & Ireland and most of Europe (the EGA area). It is recommended by the EGU and the WGU. It is standard practice in the USA.