I leave a little bit of the clearer onion-skin on before I plant.

But I do not put in the ground.
They grow in pots until the fall, and then I bring into the house. Our climate is not suitable for growing hippeastrums in the ground due to frost in the winter.

I take all the brown tunics off when I put them out. I don't leave any tunics on so the bugs and diseases cant get a foothold in the dead material. no live layers are taken off. they seem to do just fine without the tunics, but I grow them in pots. in the ground the tunics might help protect the bulbs, but ive never had problems with taking them off. in fact, I find it helps me catch rot faster because it isn't hidden by the dead tunics