Can't you just take the cart apart and remove the middle and use this. I just take the two caps off of the cart and drip directly onto the atomizer.
Yep. Here's what I do with 510 and 901 carts:
1) Remove filler.
2) Shave a mm or so off the atomizer end, so no worries about melting.
3) Remove the inserts from the mouth end.
4) Cut or drill out the bottom of the reservoir. Make sure to get all the little plastic pieces, or shavings cleaned out. What you wind up with is a (mostly) empty tube without anything to obstruct the juice drops from falling directly onto the bridge. If you look through the mouth end, it will look something like this, depending on the style of cart:
It needs to be cleaned every now and then, but that's the only time it needs to be removed.
If you have problems with carts that don't fit your 901 very snugly, just get something like these Kobalt 8" long-nosed pliers from Lowe's:
Put the very end, just a mm or so, of the cart end of your 901 atomizer into that circular void by the cutting blades. Squeeze very gently until you see the tiniest bit of flex in the metal. You're not trying to make a visible change to the atomizer, here, just flex the metal a bit.
Now give the atty a 1/4 turn or so, and do it again.
Test.
Now my carts fit almost too tightly, but that's perfect for dripping. There is no visible sign that you have done anything to the atty.
Also, I have on of
[these] on order from JC. I think they will make dripping even handier, since you won't have to mess around with screwing and unscrewing a bottle cap. Just whip this puppy out of your pocket, squeeze a drop into your atty, and vape!