JERUSALEM
My friend, firstly, i will translate the first paragraph of this text which is the only important in this case. It is written in Medieval Georgian but i can easily understand it.(Also i won't mess up the rows for you to better understand which part i am translating.)
"And he settled Cumans in convenient place for them with their families, among
them were 40000 picked warriors. He gave them horses and
weapons; and
after them slaves(dedicated), who were chosen and mastered in service,
5000 men,
each of them was Christian, reliable and experienced in courage;
and also most of the Cumans were becoming christian day by day and a big number
joined the Jesus."
I don't know the whole text but in this part the historian clearly didn't say that the King chose 5000 men from 40000 Cumans.
Secondly, Monaspa was elite backbone of Georgian army, it was professional regular force. They weren't peasants, They were aznaurs and also freemen, they were guards of the king and prince, and they were used in especially important situations to guarantee success, just like Napoleon's old guard they were kept behind the main army. But layout of Georgian army is another topic.
I don't know whether Marxists confused Monaspa with slaves and peasants or they just wisely and deceitfully used the word "mona", but Monaspa was complected with nobles and freemen for sure. Regular army were Metsikhovnes, Monaspa was elite professional and also regular. Regular in this case means that serving in the army was their profession, not more or less.
And no i didn't study anything in communist books, i just couldn't. I will even ask for the detailed information about Monaspa to one professor(real professor who was teaching in US NY and has read many lectures around the EU, including Cambridge University). He hates communists and has a different view about literally everything and he always tries to show us the truth and reality behind what was written and found.
You said: "Tadzreuli (the royal palace guards composed by various social groups)". Just remove the word "palace" and you will get the description of Monaspa.
And yes you are right, main force was Feudal army, it was vanguard of the United Georgian army, it was left flank, it was right flank, it was main cavalry force, but Monaspa was like backbone which is responsible of staying on feet after something hard hits human that can't be stopped by hands or which provides more pushing power after muscles of the hands aren't enough.
Cumans were reserve which was mostly used to hunt down running enemy, and in piece time they were raiding enemy garrisons near the borders.
In my opinion Dudebuli should be added as additional cavalry which will have horse armor, so it will be better equipped than royal force but less disciplined.
And the last, if i don't mention something, that means i agree with you.