regarding the headband tx: You wouldn't be able to look sideways for a moment, but you are able to look sideways and point the tx to the model!
Direct sunlight is always a problem for micro models as sunlight generates wind, which in turn makes flying the really small stuff impossible. But being able to fly at sundawn when the wind has calmed down would be nice, and will probably work.
The emitters are rated 100mA continuous, 200mA at 50% duty cycle and up to 1.5A for single 100us pulses, but efficiency will go down above 200mA.
These are the datasheets: