If you have installed a 6AL and it solved the issue, there is a bad? reason for that. The MSD is a multi strike with up to 15 strikes per revolution,below 3000rpm, IIRC. If your low-speed circuit is very lean, these Multi-Strikes can relight the fire as the fuel finally finds oxygen as the piston is rising on the compression stroke, and squeezing everything together. That means the power pulse may peak at some point past it's optimum point, and will therefore not be as strong as it could be. This recovers the unburned fuel that would have gone into the exhaust, but almost obviously it will take more fuel to cruise than it should have,due to the softer/longer power pulses. So the net effect may be no wins no losses as to fuel consumption. But theoretically, this is a band-aid for poor fuel atomization, and there may remain significant improvements. There is no substitute for proper atomization and a proper AFR, and a proper chamber. In an efficient chamber with a proper tune,a multi-strike is not a requirement but rather,a luxury.
Once past 3000rpm, the MSD reverts back to single strike, and the output amps of these may in fact be less than an breakerless/electronically-controlled, induction coil system. And power delivery does not usually begin until after 3000 rpm.
But it's true that an MSD can help overcome/solve, a low-speed fuel problem. It's just not the way I roll.
