Should I Use a Splined or DD Shaft?

Hi,
I used a splined end on my steering box. Then double d were used on the rest of the assembly. Additionally you may want to pin and weld all the joints used. I used two bearing supports, mocked it all up to insure it turned well without binding, then finished the welding , etc. the bearings i used also have zerk fittings for the occasional shot of grease.
(This set up is being used to fit an early hemi into a 40s plymouth. Still working well for at least 6 years now without problems)
Russ