I agree with Stan. I have several of those "Original" adjustable shot & powder dippers, but never carried them afield. I did use them to preload my little individual containers so I still considered them "Authentic". My dad was a Beagle man & when he was still living & able I went rabbit hunting with ham a lot & often carried my old original I Hollis ML shotgun. For that where fast reloads was not normally essential I usually carried an adjustable powder flask for the powder loads & just the shot premeasured. I was warned to "NEVER" load the powder directly from the flask so attached a little closed end tube which would hold more than enough & dropped the charge in it from the flask & then dumped down the barrel.
For dove shooting or any other where you will be firing a number of shots from the same position Stan's method is the way to go.
The little dippers are best used where they can be used as their name implies, Dipped, not poured into from the container. Not easy to get them full without spillage, best to dip & level off. This is not handy in the field.