In the guide it lists 8+MAX/++AR/ <20 life as Um+.
It has the maximum +MAX, and average +life. The AR is surely fairly irrelevant.
So, my guess is Um or 30PGems. A similar collection of 3 small charms with +3 MAX and +5 life would be about that too, i think (based on 10 PGems each).
Probably +9/10 MAX with +19/20 life would go higher. I am guessing that that would be like +3 MAX +6/7 life so mebbe 45PGems. Again using the 10-30 PGem range for those small charms.