Quoted from chuckwurt:

Depends on your play style and what you’re trying to accomplish. But when you’re starting out, can’t go wrong with Rosie all day.
Or rock n roll train. That requires a left ramp to right ramp/right orbit/or right target bank combo to light all the shots, as opposed to just rolling through a top lane for Rosie. But you’re going to want ramps anyway to get to jam, so should not be a problem getting song shots lit on this one.
Hells bells isn’t a bad choice either as it forces you to go after the bell to light all the shots. Dangerous, but also forces you to get your playfield multiplier as every three starts/increases the playfield multiplier.
But the biggest key to tournament play is fully understanding how the song jackpots work and when/how to collect them.

Quoted from chuckwurt:

Again, depends on the situation. Do you need 10mm or 100mm?
The song jackpot grows with each made mode shot until you drain or collect it. The collect is affected by the pf multipliers too.

Quoted from chuckwurt:

Too hard to tell. You can always check the current value of your song jackpot in instant info. Then you can decide whether to cash in that current value, build it up more, or go for playfield multipliers to get you that extra value.
If you have a good long Multiball and you’re hitting your shots, it’s pretty reasonable to expect your song jackpot with Rosie to be in the 10-15mm range without a playfield multiplier.