In general you don't want to mix active humidification systems like Avallo with beads (either Shilala or others). Shilala beads can certainly do the job without the Avallo; you just need to make sure that you have enough for the volume.
If temperature is an issue for you, you may want to follow the previously offered advice and look at a new or used themoelectic unit. (Shilala beads work great with these too
)