I have still to wait for a D1S, for the final thermal tests its something I can not do on my PCB vise
unfortunately I likely have to chop this flashlight partially open so this will also get into the prototyping costs,
because I have to do proper use of my infrared thermometer getting to max. current that the driver can sustain in the light without getting to hot
and I simply want so see how effective the solder filled thermal viases are, or if I may have to add some copper sheet on the MOSFET somehow
I would not trust contriving in a thermal probe from the LED side somehow

The goal is to get to 7 or even 8A without getting higher than 120°C on the MOSFETs hottest spot while the Lights head is 60°C hot
and also this has to take into account having a battery loaded to get proper thermal contact and voltage sag of the inserted cell to be as close to real working conditions

.

The last thing I want is selling 8A SST 40 drivers that fail after constant use because the board gets too hot
from the L4P driver we know the 4A of 1mm² white flat are no problem, but regular fibre glass PCBs have their limitations
Also the first prototypes that I have here are made on my regular 1Oz orders, while final ones will be 2 Oz copper