I think the arrows I'm referring to are earlier in the route. Or perhaps I'm getting my routes mixed up. In any case, I did find a guy that did a 100% playthrough on YouTube, if you're desperate you should turn to tsuneko / catlover_mimi Ch
Thanks, man. Watching that play-through forced me to check the other options for the 1000th time and I have finally resolved my issue (it was the time trial).
You mean these boost arrows? I can't find any secrets related to them.