You've made several errors in your posting and have 'misquoted' what I said.
First, I did not say that Langeron was 'an authority on Russian artillery and tactics?’ What I posted was a quote from Russian Tactics of the Napoleonic Wars, stating Langeron's opinion 'that most officers were not well educated and trained: there were three cadet corps preparing young men to be officers in the army, but the number of men in these establishments was limited, too small for the army, and the usual way for young nobles to become officers was to enlist in the army as NCOs and wait for commission.' This is a comment on Russian officers and their education and training, not on artillery and tactics.
Second, Langeron as a senior Russian officer, who was educated as a French nobleman, could comment on comparable education, or lack of it, among his fellow Russian officers. Wilson as a British general officer could also comment on the lack of education he noticed among Russian artillery officers. I don't see the problem here. Unless you have specific evidence to negate these two officers, then the point stands.
Third, Col Elting's book is Swords Around a Throne, not Swords Around a Crown.
Fourth, regarding the French engineer arm, while it is true that they were not a separate arm of the service until 1758, they had their own school at Mezieres, that was established in 1749, the Ecole de Mezieres. They were educated separate from the artillery officers after that date and the two arms began to separate. The engineers were also an organization only of officers until 1794. Therefore, the curriculum was not 'blended.' Engineers were not artillerymen.
Lastly, labeling someone biased because you don't agree with them is premature at best and prejudicial at worst. That isn't historical inquiry and it certainly isn't the best way of proceeding. I have written material on the Russian artillery that is quite complimentary in the past. That doesn't, however, preclude criticizing them for deficiencies in training and education, along with command and control as well as tactics and doctrine. Further, I have done quite a bit of research on the artillery arms of the period and have quoted material from the best work on the Russians army in English. I also have an excellent artillery section in my personal library. If you would like I could email some material off line to you and then perhaps avoid unpleasant and inaccurate accusations. If you would like to see some of the material I have please let me know.