thoughts of a bloated whale come to mind lol
I think you're being way too critical of yourself! You're built fairly stocky and powerful... like the proverbial brick s**t-house. There's no hiding that, and it's actually a better 'look' for a kilted man than being a skinny stick (my opinion). What you want to do is accentuate your shape to look strong. And between your pics of the shirt tucked and untucked, my personal opinion is that tucked accentuates it better. When it's untucked, you look softer and sort of "formless" around the middle.

I hope none of that sounds critical. It wasn't meant to be. You look good either way. I just think you look better with it tucked in.