You can also use any good powder designed for 12 gauge target loads, like Clays, Universal Clays, Red Dot, Clay Dot, etc.
Smart reloaders go *safe* over *economical* . Use a powder (e.g. Unique) that fills the case at least half way.
Smart reloaders use the powder that's best for the application and double check their charges.
Not too smart in my book. Mistakes happen, even with the most careful reloaders. Using a bulky powder is a failsafe.
The only powders that fit your paranoid requirement
The only powders that fit your paranoid requirement are Blue Dot, 2400, Trail Boss, and those meant for high pressure magnum applications. They are inappropriate for the 38 Special.