The LEDs use 33V max, so you plan to use 36V? Seems like planned overstress to me. Something has to dissipate that extra voltage.
Pay attention on the recommendations for the unused channels also (for your future expansion).
Watch this in your PCB layout:
"The exposed pad on
the bottom of the package must be soldered to a ground
plane. This ground should then be connected to an internal
copper ground plane with thermal vias placed directly
under the package to spread out the heat dissipated by
the LT3496."
"The exposed pad of the package is the only GND terminal of
the IC and is important for thermal management of the
IC. Therefore, it is crucial to achieve a good electrical
and thermal contact between the exposed pad and the
ground plane of the board."