While I appreciate that it is common (is it?) practice to put high power LEDs in parallel as you have shown, I suggest this is bad theoretically as there is no mechanism to share the current equally, and, in my experience it leads to early life failures of the LEDs. I had to build for my brother new PCBs for his hall lights because of exactly this problem, the PCBs I made had 2.2Ω resistors in series with each string of LEDs to balance the current, so far no failures.
LEDs have a negative temperature coefficient, so Vf falls with rising temperature. The risk of putting them in parallel is that as they heat up Vf falls unequally between the LEDs, the LED with the lowest Vf will take a larger share of the current causing it to heat up more, making the situation worse, until it takes more current than it is rated for then failing as a result.