You can't believe everything you read -- as in many cases, there is quite a bit of personal bias in things like this. I've ran blower motors on everything from points ignitions, to dual points ignitions, to magnetos fired by points, to magnetos fired by crank triggers, to electronic ignitions . . . blah, blah, blah. You can run a blower motor on just about any good ignition that has the correct advance curve, good spark and total timing settings.
With all that said, if you're going to spend money and you're going to go electronic ignition, then the next thing I'd ponder is how much boost will you be running and do you want/need to have "boost retard" in the ignition system? (Where you reduce the timing - based on the boost hitting a certain level). The last thing you want is to detonate the motor . . . and running blown engines on the street can be challenging given the various boost/load conditions and quality of gas. (If you want peak performance).
It is my guess that you have no idea how much boost you'll be making - so it is kind of a tough question? If you want flexibility to "tune the timing", then you can run something like a MSD 6462 ignition box - where you can determine how much timing to take back out of it.
I don't like the "look" of MSD ignitions on early flathead motors, but they do perform well if setup correctly (proper ground, good primary wiring, correct voltage, etc). We use both a MSD ProMag as well as a MSD PowerGrid ignition on our FlatCad blown Cadillac flathead at Bonneville. I spend a lot of time on ignition systems! LOL
