It doesnt really matter if you do it from batt end or mouthpiece end.
result is pretty much the same.. I've started to remove the rubber stopper/spacer inside. Because I allways had juice sitting between end cap and stopper/spacer. Its supposed to help prevent juice in the mouth, but I find it works just the opposite.
Have been very happy with condom method, thought it was better, but recently went back to removing end cap and dripping. You tend to waste more juice by condom method..
Dripping 20 drops in, it lasts longer before taste gets bland.. When using CM I put juice in C, filling it a bit more than half full, sometimes could get a bit more in, but it comes out the bottom again when u pull it out, so wiping it severel times on a tissue.. lots of wasted juice. Then when vaping, got some juice in batts and connecters, and it needs refilling more often... Going on more than 6ml a day...
Could vape maybe an hour or hour n a half, at the most, before taste got bland.... now with drip method, I go atleast 2 hours or more before taste starts to go away.. Think rubber stopper/spacer removed, improves the draw.