"I'm sure the Russians are going to put in writing that they can't hit a bull in the butt with a bass fiddle when it comes to artillery and let everyone else know about it. The Russian armed forces, as well as their governments, are traditionally that open-handed about their internal problems. Russia has always been an open book to the West."
There is a lot of military history literature in Russian. Anyone can learn the Russian language, and now anyone can visit the main Russian libraries or order photocopies from them and read about anything he wishes. I understand that it is not easy, but it is possible.
"Officer education was lacking, and both French emigre General Langeron and Sir Robert Wilson agreed on that point."
Both these gentlemen wrote about the Russian officers in general, not specifically about the artillery officers. And both these gentlemen were quite ingnorant in artillery: in 1796, when he was writing his notes on the Russian army, Langeron commanded an infantry regiment - Malorossiskii (Little Russia) Grenadier Regiment. Any nobleman who was able to read and write in Russian could become an infantry or cavalry officer in the Russian army after a short period of service as a NCO. But to become an artillery officer in was necessary to pass an exam at the special commission later called the Artillery Committee. Most commanders of artillery companies in 1805-1814 were graduated from the Land Cadet Corps (later called the First Cadet Corps) or Artillery and Engineer Cadet Corps (later called the Second Cadet Corps), and many of them were among the best cadets.
"Realistic artillery training was almost nonexistent at the beginning of the period"
What do you mean under the term "realistic artillery training"? Paul I organized intensive training in firing, and Alexander I continued it. The Russian artillerymen were not well trained in tactics and maneuvers, and many of them had no experience of battle before 1805, but they were trained in firing well enough. The organization at higher levels was still inadequate in 1805, but it was significantly improved by 1812.
"Russian gunnery has never been known for its accuracy, but it has been known for its mass. For example, the Russians massed at least 170 guns against Augereau's VII Corps at Eylau. Their bombardment of Soult's IV Corps caused casualties mainly because there was so much of it. Boulart, a Guard artilleryman, mentions the inaccuracy of Russian artillery fire."
Maybe you will be surprised, but there are several comments of Russian officers on the inaccuracy of the French artillery fire (cannonballs flew high, shells exploded high in the air or did not explode at all). At the same time there are comments of other officers on high effectiveness of the French artillery fire. Such comments are not more than subjective impressions from personal experience in various circumstances.