ArtMetal

My thoughts relate to the original wood pieces you will be using.   Yes it can be done but there will be very different change results between the types of wood used.  A balsa wood with a light body will burn out better than any denser hardwood item but will probably still need a good introduction of oxygen or oxygen rich air to remove the last parts and to eat up the charcoal core that will otherwise result.   Make sure the investment has both an air access and air egress that helps it flow naturally through during the burnout and beyond and then seal the lower hole after it is fully cleaned out and before pouring. I  am not sure ceramic shell is the best for this unless you are counting on doing long and continuing burnouts to give it more time than usual to remove the wood and ash.  I have done the same process a number of times over the years but used the plaster based investment and the mold included a small pipe shaft into the kiln that went to the lower hole so I could actually introduce oxygen from my gas welding torch.   I would start it out with the flame established and slowly cut off the gas flow.  To just introduce oxygene could be very dangerous and even cause an explosion so be careful with that and basically only do it at the end of the burnout cycle.   There are other points to be considering here but I assume you are already familiar with both types of investment systems.   Good luck      bpfink