General Schematic and PWM questions
This will not work. you cannot PWM that Boost converter and expect it to be stable. But if you found it works without much overshoot, ok.
THese are excellent LEDs but around but range around 50 Lumens/ W but I see 5 LEDS per board and that needs a heatsink if using 2W to get 110 Lumens from 5 LEDs after some calibration.
using any PWM controller FET or 555 timer and ?15V is the simple way and choose series R’s around Pot to design range limits.
No worries then about color shift from cool operation but it does shift with temp rise and current.
You may want to Get a portable Lux meter or calibrated camera light sensor to verify light sensor..
So for 110 Lumens you only need 2.5 W with margin and then ambient air flow or metal sink then 2.5V/5x3V=160 mA or so at 100% d.f. and 3x this from 5V or 1.25 this current from 12Vin.
For max heatsinking with CPU cooler 5 Leds x 5W=25W and 1200 Lumens is my guess not seeing the datasheet