I tried something like Mr Numpty.
I bought 2 squeezy sauce bottles from a local cheap store.
They were crap and would leak from the threads so I was about to toss them.
Then it dawned on me the tips were what i was after.
Bit of DIY and I had cut the end at a bit of an angle AND shaved the outside.
Two big issues trying to fill:-
1) VG is thick & slow
2) Air lock is the biggest issue
#1 remedy - Heat juice / VG bottle in hot water bath to thin before decanting
#2 remedy -Shaving the outside of the 'funnel' helps prevent a solid lock on the bottle, I also hold it up a tint bit as I fill - lets the air out as liquid goes in