I haven't tried 144 so can't comment. Personally I don't like (and don't need) a board wider than 75cm (iS122) in order to cover as much range as possible. I think for you a 133 is big enough, I've sailed it and have a few 95-100kg buddies that use it.
Since you cannot try the board, be careful when you try to evaluate wind strength, especially inland lakes. On a few lakes I know, slalom is rarely used, only Formula (or a daggerboard) works on most days.