People have been bobbing the hammers of their pocket revolvers for decades. I have never heard of anyone being killed by the practice. The minuscule amount of weight lost from bobbing the hammer is almost irrelevant to the ignition compared to the pressure of the spring. I would just bob the existing hammer and be done with it.
Any good hollowpoint from a reputable manufacturer will do for defense. The old "FBI load" of a 158 gr SWCHP was the standard for years, and will still work, though it is a +P round. The 135 gr Speer Gold Dot load is supposedly optimized for snubbies and is also worth a look.