I used to use a 2.8-2.9, until I watched a video that Jason from CSO uploaded, saying that professionals use heavier weights, around 2.11-2.13 (not accurate, I know), and as a younger lad who knew no better, and since I could hardly bat, I decided to start going heavier. (I had nothing to lose, and wanted to try hit those big sixes!) I did find that heavier bats tend to pack more of a punch, I think I started off using a 2.11, which felt a little heavy, but connected nicer with the ball. From then, I've kind of gotten used to slightly heavier weights, and since my cut shots and pull shots were very weak then (Still aren't perfect, but I can at least connect!), and I had very limited shot selection, I can't give an accurate observation. My current match bat weighs about 2lb 12.5oz, which I feel in my head is right on my limit in terms of weight, but I just love the bat, it feels right in the hands and almost every shot I try play with it just feels right. (I like 2.10-2.12) It would all be down to the craftsmanship and quality of willow (Had a guy pick up the bat, and said he thought it was around 2.9, I think it picks up like a 2.10), and I have a feeling that the ideal sort of weight range I have is quite a wide spectrum, (2.9-2.13) but I feel pick up is what is more important. In the end though, it's about what you're willing to compromise in your game. (Speed and variety, or power) I have a fairly limited shot selection anyway, so I tend to go for more power.
Dead weight is still pretty important though, and I would say to avoid going out of your weight range. General rule I apply is maximum an ounce and a half above or below 2.11. (Try not to go below 2.10) If you ask forum members who are very picky about their bats, (Procricket Dave springs to mind) I'm sure he would tell you the same, he had a lovely B3 Trott bat which weighed around 2.10 I believe, picked up beautifully for him, but he felt he was a bit late on his shots. Weight reduction down to about 2.7 and he was a happy man!