I wanna make a suggestion. Can you guys consider Fortissimo EXA Akkord Bsusvier? I believe its the same as the first game Fortissimo Akkord Bsusvier but with a true route and voices. It's made by 2 companies, La'cryma and Circus (Circus made popular games such as the Da Capo franchise) and apparently the story is similar to that of Fate/Stay Night.
Here's a link to the OP song:
If you don't like that OP, know that a slap is coming your way.