The TA alternator has plenty of spare capacity (at least the 650 does). I ran two 55w spots and heated grips throughout winter no problem.Note the Transalp generator has only limited power available above the standard lights, and from previous threads it appears that there is only enough power for continuous use of one, not two, standard power spots, or two if you put lower rated bulbs in.
If you haven't already, try using the search facility, or rummage through the Transalp threads by eye, and you will probably find a number of threads about spots and power capacity for them.
I stand (well, sit down actually) corrected.The TA alternator has plenty of spare capacity (at least the 650 does). I ran two 55w spots and heated grips throughout winter no problem.
I think the max alternator output is around 375watts. Normal running uses less than 200watts so there's plenty spare as long the revs are up. Around town could see a drain on the battery.