Gear for lap times - period.
If you run ANY drag brake, your temps will be higher than someone who doesn't. If you use brakes, your temps will be higher than someone who doesn't. If you don't use drag brake, or brakes from the Tx, your temps will always be lower than someone who does. So, you can run the same ratio and get very different temps depending on driving style.
If you race in Florida, you will likely get much higher temps than if you race in Vermont. Ambient is critical.
Through all of this, there is a sweet spot that will get the clock down to that A Final time, and it has nothing to do with temperature. I am not sure who started this thing about temps, but it is mostly a red herring, except where there are high track ambient temps.
The speedo looks after itself (shuts down) and your thumb looks after the motor - if you can't hold your thumb on the motor after a race for more than one second, it is too hot and losing performance. This is how we geared BR motors, and it still works with BL.
There are three things that will get your BL into the A Final - gearing, gearing, gearing. HTH