13500 lumens would require around 200w. I’m guessing your using stock leads on your multi meter so you’re unable to measure more then 1.5 amps. If your Skyray was really running 1.5 amps that would put it at 6w, so a BLF A6 would be brighter then ur 9x led Skyray.
The limiting factor with flashlights isn’t heat its voltage sag. The shelf was originally removed from Skyrays because people complained about the heat, so they removed the shelf and the heat problem was solved!
Unless you plan on fitting a small CPU heatsink under the shelf you will find the PCB will generate heat faster then a fan could shed heat from the heatsink, and at that point you could of just added more mass and gone down a mode! Whatever you decide i’m sure it will be fine 25watts is what most stock soup can lights do.
Have a read around theres plenty of information here:
Heatsink in a SRK @ 14:20