I am using my DIY Orange Cream, tastes like a Creamsicle. I have it around 10mg. My coil is reading 2ohm so I have it at around 4.7volts. Nice and smooth and it really brings out the flavor. I have noticed the Genesis style atty, or at least the Zap, can handle higher wattage better than most attys.
Mini Cooper, if you used to doing 24mg, I would really try a lower MG juice in the Zap, I guess it depends on how you are vaping it also.
I have changed the way I inhale on the Zap compared to other configs. It is kind of like Busardo said, its like relearning how to vape. I do a mixture of a primer puff then straight inhale, then a normal pull all tied together. I never straight inhaled in normal atty and cartos, would kill my throat.