I wouldn't worry about how much weight you can handle with chins too much. As long as you can add some weight, you should be fine. I was really weak in chins when I first started using them. Right now, my 15 RM is barely over my bodyweight, so I just increment every third workout with them. You'll gain strength in them fairly fast, and you will definitely see growth.
Also, once you get to the negatives, chins are easy to do negative style and when you do them that way, you WILL feel it in your lats. In your forearms too, probably. I did anyway.