Just a thought that occurred to me...
Using Naranappe the 10th, with Reporter boost. Lv. 5 Memory Appeal. With Naranappe, a Single -> Duo Appeal will fill the meter. Subsequent Trio Appeals will also fill the meter by themselves. Furthermore, you can fit a burst inside Memory Appeal chains without breaking them. So...
Single Appeal -> Duo Appeal -> Burst -> Trio Appeal -> Burst -> Trio Appeal -> Burst -> Trio Appeal -> Burst, regular appeals to the end, burst if you can.
For an upbeat song like Do-Dai, I think you'll hit five easily. For my song, well... that fourth burst is all you get I think. i will have just enough beats to pull this off... maybe. Wondering how this'll affect scoring, as opposed to dual-routing for two or three bursts. Haven't tried it out, since I've never gotten Lv. 5 Memory Appeals.
Also, for special fests - Ran into one that maxed out at four Memory Appeals. So...
Regular Appeals until I know I'll fill I'll fill the bar with a Memory Appeal, then fire it off and Burst.
Regular Appeals until they start spamming, then go one-for-one. They'll use three, I'll use two, they Burst, and top it off with their last Memory Appeal. I'll still get to my next burst faster than they'll get to theirs.
Regular Appeals until I get a full bar. Hold the Burst until they get close to a full bar, then Burst.
I don't know why holding the burst stopped their next burst (as opposed to firing it immediately, where they could get in a final burst and win), since by the end of my burst the song was still going, but that did it for me. (Once.) For completeness, this was the Lv. 8 Fest in the west (in Chuugoku/Shigoku). Just shy of Lv. 16 I think, Lv. 3 Memory Appeal, Reporter boost, Mail boost (not sure if that matters). Naranappe the 10th, less than optimal equipment (as in, no top-tier equips since I don't have them yet).
Didn't see anyone saying how they won a special fest without letting the idols rock house by themselves, so I thought I'd toss it out.