Standard 510 cartomizers and atty/cartridge setup are WEAK! way too weak to keep up with a real smoker.
There are a thousand different ways you can go to get a better vape, this is what worked for me-
Look into Boge LR cartomizers, they have much greater output at the expense of shorter battery life due to the lower resistance of the cartomizer.
Another option is getting an Ego twist variable voltage battery, place a stock 510 atty or carto on it and crank up the voltage for greater output.
Dekang RY4 18mg is one of the worlds most popular juices available today and is my main daily vape.
DSE 901 is old tech in the
vaping world and for the price of a DSE kit you could buy an Ego twist with a box of Boge LR's cartomizers which would outperform the 901's in battery life and vapor production.