I bought a Hyrda-SM electronic humidifier and I'm happy with it. It's the right size for my humi and only have to fill the resevoir about once a month or so.

I don't use the hygrometer on it though, I have a separate digital one I use. I just adjust the RH level up and down to suit that hygrometer and make note of the setting for if/when I have to shut it off. At present the humidifier is set to 73.0% RH and that holds my humi right at 65% RH (real).

I haven't tried beads myself yet, but I'm sure I will eventually when I have make my first coolerador or start using the drawer on the humi itself.