I'm a Fan of pierced downstems. For my beaker i like a downstem with 6 holes and a little hole on the bottom but for my tubes i like downstems with 8 little holes and open end And you ?
I agree with Alex k but I've heard its hard to get all the diffusers to fire together with the gridded d/s
sov 180 grid or alex k showerhead is probably your best friend. If you want cheap showerhead downstem I think SSFG still them.