well, the quality of your piece smacks of professionalism. engraving is not a race. with practice, one can learn of techniques and simple time saving tricks that do lessen the time needed to do quality work.
yes. i cut criss cross grooves all over the plate. this not only aids in the glue forming a good anchor, the grooves allow the alcohol to penetrate much faster for a very easy release. send me yer mailing address and dimensions of what you want. i'll send you a piece.
there's really only two choices--- hss or carbide. i know of no other special alloys for cnc or pantograph work. there are diamond points configured to create wider, frosty looking cuts when used in rotary mode rather than just the typical drag or scratch mode.