I think Ray has pretty much answered you question. If you are turning between centres without bushes then you do need a dead centre in the headstock and a live centre in the tailstock. The tailstock needs to be brought up gently and tightened enough to prevent the blank from revolving but not so tight as to splay the ends of the tube. Cone bushes are less likely to damage the tubes and plastic ones probably the least likely of all to do so.
Thre again, there is the overriding question of whether CA is really the miracle finish it is made out to be. Lots of people, Woody for example, don't use it because of the fumes and as you have already discovered there are plenty of other options to try. as Ed says "Restricting your scope to a specific type of material limits your creativity".
