Timing retard function at startup is very helpful. But you can do it one better.
I hit the starter, and engine starts turning over, then I flip a switch
which cuts in the MSD box, and engine starts. This way you do not have your
starter fighting against some cylinders that are already firing.
But you may solve your problems by just reducing your initial timing
by 4 or 5 degrees.
Put the switch to the MSD box on the small red wire, not the larger red wire. This flipping
an ignition switch after the engine is turning over really saves on starter life, other components,
and electrical life (due to starter drawing less amps)
Also, insulate your fuel lines, to prevent vapor lock, because when sitting, things heat up.
You can use the pipe insulation they sell at Home Depot. I tested it, it does not burn.