Wooden revolving tail centre Advice please

I am planning to make a number of wood cones which will be attached to my revolving tail centre using plastic threaded inserts epoxyed into the timber

My question
Should I make the cones as a spindle blank or bowl blank grain orinetation

I doubt it would be a show-stopper whichever one you pick.
I think I would go for spindle orientation since it may well be more dimensionally stable and easier to mount to turn.
Epoxy and plastics sometimes don't make a good bond but this should be a very light load on the insert joint and if it spins it won't cause the piece to fly off the lathe anyway.

Your bigger task is going to be making all of the work run true with the axis of lathe. When I make those kind of accessories, I put the live center in the headstock, drop a nail in the locking hole if you have such a thing, wrap tape around the live center to retain the nail, then true of the center I made. Oneway and the knockoffs have this locking hole so you can spin on the accessories. Without that truing up, you can get a lot of runout.

If it's just a stabilizing cone for support, MDF is preferable for dimensional stability.
You can directly thread it, insert isn't necessarily needed. You can stiffen or reinforce the the threaded area with CA glue.
A tap that matches your live center threads comes in handy for making specialty pieces, no need for inserts in most cases. Good to have in the long run. IMO

^^This. No point here in working harder.

Thank you to everyone for your help and comments I had not thought of using MDF and using the headstock to make it run true with the axis is an important consideration

The Robust drive & live centers share the same 3/4" 10 TPI threads making it easy to turn accurate workholding cones.

https://www.turnrobust.com/product/live-center/

Rubber Chucky?

https://www.rubberchucky.com/store/c..._CONES_.html#/