First, there are two types of Ivory Joints, Corded and Solid except for the pin. The corded joint is the most stable of the joints, for the following reasons.
1) Solid Ivory joints will expand and contract with changes in temperature and humidity. Subsequently the feel of the cues hit can change. Also with time solid Ivory joints can become brittle and crack due the changes outlined above.
2) The corded Ivory joint is mainly for decoration, and will not effect the cues hit due to expansion and contraction. It is also much more stable long term.
3) The stainless steel joint is very stable, will insure the cues hit remains firm and repeatable at all times. This joint in my opinion has the firmest hit of any joint currently being used.
If I were you, would either stay with your stainless joint or try a wood to wood joint. However, if you must have Ivory, I would go with a Cored joint for longevity and stability.
I hope this helps!!!!
Have a good Night!!!!