How much fat you can eat without gaining weight kind of depends on how many carbs you take in, plus how you lose weight as an individual. For some, calories don't seem to matter as long as they stay under 20ish carbs, while some may not lose if they eat too many calories from fat, even in the absence of carbs. Gender is important. Most men I follow on low carb forums seem to basically be able to eat as much as they want, as long as carbs are low, but many women have to also watch calories. I personally don't worry about my calories, as fatty diets are very filling, but some have trouble losing if they don't keep an eye on their intake.
Remember, you are unique just like everybody else.