Before I answer the question about the starting load, let me point out that there can be some legal problems unique to using handloads in a self-defense shooting. Check out the legal section of one of these sites and see what real "briefcase toting attorneys" say on the matter.

Legal | The High Road
Law and Civil Rights - The Firing Line Forums

That said, if we ignore the data in the OP superseded in later editions of the manuals, there is more or less a consensus for a Maximum load of about 4.5 grains. This would indicate a Starting load of about 4.0 grains.