I was told not to use one without the other. A hard part & a soft part dont mix; the softer one will be stripped out in the spline area if serious power is made ; do all or nothing, go all hard (billet) or go home doug.
this is talking about the billet ring gear and carrier with a billet input shaft.
I have a billet f. drum like you do but a hardened input shaft in my extreme auto tranny now.
I have a billet input shaft, billet drum, billet carrier/ring gear in my other trans i just took out with only like 3000 miles & 1,,, 8lb. transbrake launch that i MAY sell when i pull it apart. I havent decided yet. Im gonna hold on to it for now but tommorow , you never know..