Love the Nalgene bottle! I am going to try it!
I found the trick to get the flow started is a strong side to side shake, in the horizontal plane, not vertical tapping. The grinds seem to dam up sometimes over the pour spout, and a strong side to side or swirl motion will get the flow started. Once the flow starts a few more shakes gets 80-90% to come out very easily, no banging. If it is being more stubborn, I will quickly flip the grinder upside down and give a little quick shake, turn it over, side to side shake, and then I get the last 2-3 grams. (This all takes less time to do that it took to type it out.)
On another note, I have ground over 20 shots today, and one big change I have made is not going after the last .1 to .3 grams anymore. I was getting 17.6 to 17.9 back from a 18g load, and then chasing that last bit with 10-15 seconds of extra banging and tapping, I decided it is not worth it. I now put in 18.5 grams each time, grind, dump to my flexible plastic cup, and then fill my double basket with OE funnel on the scale. I fill to 18.00g and then stop, tamp, and shoot. This has made the shot preparation easier, faster, and it looks much more elegant to anyone you are showing the grinder to, that extra 10 seconds of banging to get that last .1 to .3 grams looks crazy to some people, but I totally understand the feeling to want to get it all. I have found stopping the banging, tapping, shaking, poking and such has made me enjoy the grinder more, and keeps my routine from getting side-tracked by quests looking for the wooden hammer of Pharos.