I dont like poking any larger hole in the stopper than necessary. Why do it if not have to?I been using 20ga to fill lately. Works fine. 23ga gets real slow to impossible when my igloo is kind of cold this time of year. Ive never had success pushing any Suspension products thru anything smaller than 23ga. Suppose it could be thinned.Proper injection protocol is to use a new needle to inject. They dull on the rubber. Hurt more.