How are you planning to use the light body, in it's original form or just the head ? The light as-is has quite a bit of surface area, and with the air flow of riding you'd probably be fine at 2.8a. I have the MTE 2 mode P7 C bin flashlight and it runs at a full 3a since it's direct drive. Never seen it to have any overheating issues when moving.
On the other hand, I'm currently in the latter stages of a dual P7 D bin based on achesalot design and running a pot dimmable driver up to 2.75a - it gets HOT, too hot. I haven't cut and installed the heatsink materials on the main body yet, but I'm already anticipating the need to sink some heat into the mount system and even to the bars, so the mount will need to be aluminum and well attached to the light body.
On the other hand, I'm currently in the latter stages of a dual P7 D bin based on achesalot design and running a pot dimmable driver up to 2.75a - it gets HOT, too hot. I haven't cut and installed the heatsink materials on the main body yet, but I'm already anticipating the need to sink some heat into the mount system and even to the bars, so the mount will need to be aluminum and well attached to the light body.