I take it that you use the metal tubes? How do you fill them? How do you know when they are completely full? I'm tired of the cracking clearomizers and thinking of trying the metal tubes,
I use the metal ones stock out of the box...
After you've used a CE2 a while, you can usually tell when it's time to refill. It just stops vaping
Before I refill, I do put a drop on the atty and fire it just to make sure the coil still works:
I don't worry about wether it is packed to capacity or not...I just grab a syringe and shoot about .8ml in if it's a regular CE2, or around 1.7ml or so if it's an XL.
You can be careful, take it slow, and watch for fluid to start coming out the opposite fill hole, then reverse and suck out just a tiny bit (to leave some wicking air space in there)...but if in a hurry, I just shoot it in slow and steady then blow out excess juice and wipe. Sometimes I do waste a little juice in my haste...but it's fast and easy.
It didn't take me long using these to get a feel for them. They do last much longer than the clero sleeves, and they don't look so much like you're walking around with some kind of strange crack pipe if you like to vape in public.