Should I normalize single-shot samples?

[soma]

I suggest sequencing the entire set you want to sample and keep velocities controlled as much as possible (use copy and paste if doing velocity layers for different sample sets). Set you hardware volume to the max possible (if you have more than one hardware component in the chain you need to check each link for clipping). Use a level meter or analysis tool to find the maximum volume of the entire set and adjust the software trim so that you are -.2 db from max.
This way you are keeping the samples's relative volumes in tact and you have minimzed the noise to signal ratio while still leaving a very very small gap to play with.