If your referring to my grammar, I am just a horrible and lazy typist. I am actually going to teach business classes being a double degree in business admin.
The lazy excuse doesn't work for the wrong form of the word "your" being used there. Don't teach your students that bad habit!
Smart assness aside, 150 was way too short for your weight. The reason why rental shops are taught this method is to get through the masses of renters. If they had to ask the weight and find the size based on that, it would take them much longer. This unfortunately has spilled into the outside world and big box retailers are the worst offenders of this sizing myth. Anyone that tells you to size a board based on how far it reaches up your body does not know what they are talking about.
Each board will have a unique weight range for each size. This is even the case within the same brand. Compare a Ride Machete to a same/similar sized DH2 and you'll see the weight range is different.
You're likely looking at a size range of 156-162cm. Optimally, you want to find the size where your weight falls close to or on center. You can size up/down as well if you like. Just keep in mind that going lower/below the range, will mean the board will flex stiffer than intended. Opposite rule for going higher/above maximum.
You won't need a wide board so throw those out of the equation. Pay attention to the 159cm+ sizes as some of them are actually mid-wide/wide models. Keep the waist width under 26cm (board will be wider at the binding insert points).
Although I have no experience with Bataleon, they don't sound like a good choice for someone who is 1) fairly new 2) has been riding traditional camber. On all accounts, I hear the TBT feels very different. Some love it, others hate it.