I only have single monks myself but (and I assume doubles are the same) they have a bit of elastic under the buckle that gives the shoes a bit of give, like laces do, but yes probably a touch less forgiving. But I've never sized down or anything.
That looks too trendy for my liking - it is noticeable short and has noticeably skinny lapels. It also has the air of an orphan suit jacket. Buttons in horn or metal would help that. More classic would be more versatile.
Just accidentally opened every single file in my downloads folder. Couldn't cancel it after I realised what I'd done, had to sit and watch it happen for like ten minutes, then spend another 20 shutting them all again.