I'm another EG and Milk drinker.
Always blue top or full fat from the house cow. I don't consider light blue or green tops to be milk, they're coloured water.
NZ milk grades are:
Red top: pure cream.
Silver/Grey top: full milk with all it's fat and cream, content varies seasonally and is often not available in winter.
(dark) Blue top: standard milk, depending on season some cream/fat is added, other times is skimmed slightly, same milkfat profiles year round, no matter what the cows are providing.
Light Blue top: skim milk
Green top: low fat skim milk for the diet nuts.
WHICH milk you use changes the flavour of the tea...