Is there a best practice for when and how to remove the withered blooms?
Certified GKH Gardening Expert
If the pods do not swell from pollination, then they can be removed as soon as the flowers fade. You can remove close to the base with a sharp clean blade.
This article will give you more information about their care: https://www.gardeningknowhow.com/ornamental/bulbs/amaryllis-hippeastrum/amaryllis-care-instructions-how-to-care-for-an-amaryllis.htm