The Angelic Masterclass was what I call "Phenomenal". It was life changing. I truly thank God for His wisdom and knowledge that was birth out. God used the messenger Prophet David in such a way, I believe, will draw many to seek the Lord and draw closer to Him. The Lord gave insight revelation, and instruction. Prophet David teaching is some what like (Paul -“And my speech and my preaching was not with enticing words of man's wisdom, but in demonstration of the Spirit and of power:” ) Blessings.

Understanding the hierarchy of Angels and the spirit realm has given me much clarity and understanding of how to approach life and spiritual matters. Knowing the different functions, offices and positions of Angels aides in our communication with them and understanding the ways they communicate with us. 
You provided many profound nuggets but this one really stuck with me. “We do not pray to Angels, we communicate with them.”