(revised 2/2013)
...Violin plate graduation, even of famous violins can be quite varied. However, I imagine this following information will yield consistently professional results which will survive in constant use for several hundreds of years.
It is said that"good violins have been made for centuries that are 2.6mm thick'" for the top plate (spruce wood) and this is what I recommend now.
...My last three violins produce exceptional sound performance with these plate graduations.
...The back plate graduation is based on the analysis of the measurement of famous Gruanarie Del Jesu violins shown in the violin making book.
... The outline plan is to make the back plate tap tone, when complete, to be between f and f# (below middle 'C' on the piano) with both the upper bout and lower bout matching and the lower bout tap tone of the top plate to also match the back plate. (the upper bout of the top plate will be a lower tap tone...more on this later).
...So the back plate should be completed out side ready for varnish and then the inside graduated to the plan shown (see link above).
...Next the top plate is completed with the inside graduated to an even 2.6mm. The lower bout tap tone of the top plate is measured and then compared to the back plate result with its initial tap tones (once evened out so that both upper and lower bouts match).
...If the back plate then is adjusted so that it is as close as possible to the top plate result and still be within the f to f# range (which is very important). The top late is then adjusted to match the final back plate tuning.
...At that point the back plate is ready to be joined to the rib structure and the top plate have its bass bar fitted and then its ff holes marked and cutout. At that point, the completed top plate is also ready for assembly {allowing for any ground treatment to the inside of the plates that may be desired to be added first.}
...At this stage, the potential of this particular violin is set, as it can be no better than the potential of the completed sound box.

David Langsather February 2013 A.D. Salem, Oregon USA