I made the 104 for ds2 and 116 for ds1. I didn't add seam allowances but I should have. The pattern runs quite narrow. It is pretty tight around ds2's tummy but he'll probably only wear it for my sister wedding so I'm sure it will be fine.

I did add 1" to the length because they will tucking them in to their pants and using belts.

This was my first time doing the stand collar which took a long long long time! I did add the 1cm sa to the collar and neckline as they instructed. I found that collar a tad too long and had to shorten it on both. Overall the instructions were good and the pattern is super duper cute.