You can use Mediterranean olive wood but you have to wait long enough for the bored out wood to dry before you glue in the biggest core that will fit. Even then there may be small short surface cracks that you will need to fill with a pigmented epoxy filler. The secret is time and patience and 10 years from arrival of the wood to the finish of the cue is is probably about right. The problem is that the wood cell structure is a closed cell and moisture can't be forced out quickly, even by laboratory strength vacuums.
Thanks for the info Paul. I have 6 pieces of highly figured Bethlehem olivewood that I've had for 3 years. I am using the weight measurement method and they keep losing about a 1/2 ounce every year so far. I plan on coring, just haven't done it yet.
Dave