Manufacturers, brands, skins, maintenance, stands, sticks, michrophones and other accessories for congueros can be discussed into this forum ...... leave your experience or express your doubts!
I got some pairs of those and at this moment working good for me plus sometimes if I go out with my friends to practice they keep the bottom rim safe. But the modification its a good idea.
I too have tried those little rubber feet, and wasn't too impressed.
Right now I am using the gibraltar "low seated" conga stands, and I really like them.I can range between almost touching the floor to about 4" up. I usually play them at about 2" off the floor. They are very stable, even on uneven terrain. And you can even tilt the congas some in the stand, to make it more like the angle when you hold a conga between you legs.
I included a pic from the web I found with a quick search.