LED wiring and driver selection
That's too many LEDs to be running parallel strings. 

I ran some experiments on two parallel strips of 16 Lumiled Rebel ES LXML-PWC2 white LEDs.

One experiment the strips had a Vf of 43.29V and 43.85V 

When driven with 375 mA the currents were 240 mA and 135 mA.
When driven with 770 mA the currents were 450 mA and 320 mA.

In another similar experiment with strips from the same LED reel the strips when in to thermal runaway after about 12 hours. 

I used three sets of Bridgelux off the shelf EB-Series Gen2 strips with  Vf's of 37.94, 37.86, and 37.77 @ 500 mA.
Each set was two strips wired in series and the three sets in parallel. 
When connected in parallel the Vf was 39.06V.
When driven with 4173 mA the current in each set were 1515, 1430, and 1228 mA.

When I tried two 35V (34.9 measured) CoBs in parallel driven with 1227 mA the currents in each CoB were 764 mA and 463 mA.