When it comes to cufflink shirts, I recommend french cuff shirts over convertible cuff shirts. There is nothing formal about a convertible cuff shirt. Cuff links formalize a shirt and, therefore, demand French cuffs.
There has been much confusion that men’s pocket squares are somehow directly linked only to neckwear and are to be worn only with business suits and formal wear. Nothing could be farther from the truth. Here’s when to wear a pocket square.