I have two ways and have never had a problem.

The first is those little plastic medicine cups already mentioned. They have grams and ounces so it is really easy to mix up 3 or 4 different sized batches. This is pretty fool proof. After the epoxy sets, just pop it out and reuse container. I did learn one trick. Use a magic marker and put a tick next to the measurement line. That way you don't lose track of which measure you are using.

The other technique is to take a 12" ruler and rest one end on the shoulder of the resi or hardner bottle. Then I lean the rul;er against the head of the pump. I slowly push the pump down and when flow starts (often there is some lag because of pull back), I go another inch. Then I switch to the hardner bottle and do the same except go 1/2 inch. You can do larger or smaller batches by changing the measurement.

Also, "If in doubt, throw it out." On both large and small batches, I have had a couple of times where I wasn't sure I had measured correctly. It is easier and cheaper to throw away something occassionally than to fix the result. I had read too many horror stories of mismeasured batches on the BBS. Turns out the batches were OK, but it was cheap peace of mind.