Have this card set and a "Shiny Black "C"" in your graveyard. When your opponent synchro summons, you can remove "C" from play to destroy the synchro monster immediately, then activate this card.
Use cards like "Bottomless Trap Hole" on your opponent's Synchros. Although they do more than destroy, their wordings still count toward meeting "Grado"'s condition.
If you have multiple copies of this card you can use more that one in a turn so you can chain them together or if you play one and draw into another you can play that 2nd copy.
This card has synergy with monster-exchange cards such as Creature Swap. Summon a low level synchro monster, Swap it for a more powerful monster your opponent controls, destroy the synchro, then activate this card.
This works even better if it was a monster like "T.G. Wonder Magician" or "T.G. Power Gladiator" because you can draw another card in the process; they can also be swapped with "TG1-EM1", further increasing the viability of this combo.
Since a lot of players use XYZ Monsters, consider putting this card in the Side Deck first. Then if you know your opponent's Deck plays more Synchro Monsters than XYZ Monsters during the first Duel, then that is a green light to play this card during the other Duels.