I think that I'm between meso and endo too. When I'm fit, I'm hourglass shaped, when I gain weight I shift to being more of a pear. My legs can get quite muscular and I'm usually a size 10-12 even at my target weight.
What's working for me is following the Jenny Craig program, doing hour-long cardio sessions 2-3x a week (spinning, kickboxing); alternating upper and lower body training. I'm making good progress with arm strength but I'm not seeing the definition I want, so I think I'll change it up soon. Other than that, I'm happy with my progress.