1. If too uncomfortable, you could just reduce the voltage applied in Settings. Some people have less palm skin resistance and may feel pain, others may not feel much, but also is up to the frequencies - the feeling is much stronger at low frequencies and wet hands. The bad feeling could be reduced by wrapping wet kitchen paper around the metal cylinders, or just by touching them, instead of holding with full grip.
2. Some people feel they are too strong and prefer 10s pads on the colloidal silver port. You can also put the hand cylinder cable on the CS port. It has a frequency limit that keeps the discomfort to min.