Got this from somewhere else but it might help u out. Also I'd suggest adding Heavy cream to the milk before you boil it, to increase the fat content. It also makes milk drinks richer.

Spiked Milk is very easy,
although a couple tips in case you do not already know:
if using milk make sure it is full fat , the gay milk(Homo)hehe
THC is going to migrate to the Milk "Fat" so skim or reduced fat milk will not hold as much
The best would be Raw unpasterized squeeze the titty your self in a glass milk, but unless you have ready access to Raw milk, Homo is fine .. do not go order Raw Milk from a dairy farmer in Idaho off the net.. Now if you was making Cheese.. consider it.... but any way i am Rambling again lol
for milk, the smaller the pot(the happy grass not the cooking vessel) the better:

Chop small with chef knife.. lot of work

Coffee grinder OK.. unless it is super sticky..never put liquid in one to wash it out..experiance talking..no i guess inexperiance hehe

Food processor.. Good can rinse with the milk..

Blender.. Perfect can throw the milk right on the weed and hit liquify

ok any way when heating the milk, it is better to steep it and hold it slightly before boiling,for 45 minutes to an hour
got a thermometer? good temp.. 165 to 180f
if not just heat it slowly till it gets to that point you know it is going to boil( steaming a little that sound the pot makes(now i am refering to the cooking vessel, the weed does not cry or scream like live crabs do hehe) then back the heat back a hair, milk scorches easily, Stir often , or constantly if you like especially when it gets hot
boiling milk can scorch very quickly so it is easier not to boil it
then strain
I am not a big milk drinker..and do not know off the top of my head the amount of milk fat in milk or the actual amount of THC a measurement of milk will hold
i will assume a quarter of Canna would easily work with a cup of milk,
may be start with 3 to 4 grams(1/8..half of a quarter with a cup of milk, and consume 1/2,unless you normally puff more than that, because we will assume you are going to get at least 80% of the THC and smoking it you lose alot .. your lungs can only hold it for so long lol and can only .. oh my rambling again lol
so go from there
would not be to hard to work out a ratio that works for you
Although now i have this new unanswered question..
and my Boredom is setting in, i may have to look into this further, i will post it on this thread if you really want to know check back ..
I am not Big on milk but i do like Cheese..
Now there is a idea..