if you want to push higher watts, you need more airflow. its not that you cant maximize those 50 watts, its just your technique and or device might be wrong for that particular task.. which doesnt make it any better or worse than anything else tbh.
you mentioned you want to be able to 'blow fluffy clouds' or something like that. that doesnt come from a long slow relaxed hit. it comes from a more powerful inhale.. a change of technique.
another thing to take into account is that when
juice is vaporized at higher watts, its effectiveness in delivering the nicotine is greatly enhanced. most cut down their nic % by 50-66% (ie: its not uncommon for both 12mg/ml and 18mg/ml users drop down to juice containing just 3 or 6 mg/ml of nicotine.. this makes the throat hit smoother and doesnt give you a nicotine overdose.
another factor to consider when cloud making is that you burn through juice a LOT faster than you would at lower watts/ less airflow.
for your setup.. if all you have is the .5ohm coil.. use that.. open up the airflow all the way on the subtank, and set it for i dunno.. 18-20 watts. when you press the fire button.. give it a half second or so.. and then pull very strongly through the drip tip.. dramatically increasing the amount of air that was going through previously...
check the results.. for flavor... vapor production.. and negatives like excess heat...
go up or down the watt scale to find a sweet spot.. also you can start playing w/ the amount of airflow.. but w/ more watts, almost always.. you want more airflow.
it can be fun to chase clouds... its silly.. but there is something really neat or cool about seeing this tremendous amount of vapor escaping your lungs and enveloping over everything.. making whats in front of you vanish momentarily.. exhaling a partial exhale that dwarfs anything you were able to do at lower watts.. and then fully exhaling surprising even yourself that it just keeps coming out...
but it does eat up that juice...