I am still using carts on my M401's tiny carts (but with blue foam stuffing - still using the same 1st cart). I am using cartomizers on my other two PVs - KR808D-1 which is a cartomizer unit with a decent selection of prefilled cartos and some types of blanks, and 510 which can use atty+cart or has a variety of blank cartos and some filled ones available). I got a week out of a carto by topping it off whenever the vapor let up (didn't want to singe the stuffing since that would ruin it)
Shizzle - superminis and carts won't cut it if you want more drags. You need to get a model with options like cartomizers, for example a Joye 510. Not much bigger than a supermini - almost as slim as a cig. LiteCigUSA.net is one place that sells them (maybe blank only with blue LED - you may be able to find white elsewhere). And they sell the cartomizers I use
510 Blank Cartomizers
FreedomSmokeUSA has white manual 510 kits as well as black ones (and lots of juices)
FreedomSmokeUSA
You can also get a mega atty for it and mega carts which hold more juice but the problem with carts is the top need to be wet. Blue foam stuffing can help a 510 cart wick the jucie better (strictlyejuice.com has precut blue foam stuffing for standard 510 carts). But getting more drags than that needs a cartomizer (and a cartomizer might last a week or more, maybe longer with cleaning - not forever like a cart). Or you can step up to a fatter battery model Ego (which is 510 based) and use the tanks.
510+cartomizer is enough for me. With standard batteries the battery life is still short like a supermni (180mah or maybe 1.5-3 hours, maybe less if you vape constantly). You can get a PCC and charge one battery in your pocket while using the other. They also have longer "510 mega" batteries and longer PCC (the longer batteries last 1.5 times as long and make the 510 a 130mm unit with the cartomizers I linked above)
Get manual batteries. Manual 510 batteries are sealed on the threaded end so safe from getting killed by juice leaks, And manuals are actually less work and give a more consistent drag.