With regards to pre-made veneered or even non-veneered blanks...quite often you get what you pay for. For me, choice of woods used, the absence of glue lines, and the 'tightness' of the blank are all important factors.
While I am not a cue maker, I have been told that nothing can be more miserable for maker than working on a poorly crafted blank...which is why many will not accept customer supplied pre-made blanks for a project.
Lisa