I can attest to the magnito issues. When they go bad...they just don't work.
I chased one a couple of years ago at Celina. I even missed One Lap Vintage Exhibitions as a result (Mark Weber - Race Director knew something was wrong and stopped over to see if he could be of help).
When I sent the Mallory Sprint Mag (they only come locked) back, all they did was put a new cap and rotor in it. The test results were given to me. On a 12amp Mag, it was putting out 12.8Amps...so, it's plenty strong.
Spinning the engine and then firing is easier on the starter. Sometimes the engine will want to kick back against the starter. Getting the whole assembly rolling and then throwing the ignition on will allow the engine to spin faster espically with the prop engaged.
Oh, if anyone has ever noticed, I ALWAYS warm the engine up on the trailer in the morning after checking valves and doing general maintenance. A warm engine will start easier than one that is cold. If it's been run an hour or two prior to being put in the water, it will start easier and it's just better on the parts. For one, the oil will be warm and will start flowing sooner to the bearings.