Cheap reloading trick for trickle charge.. Use a 308 fired case with about 1/2 fill of powder and roll between thumb and fingers. You can drop 1 or 2 flakes/sticks of powder over the scale pan at a time. It is much faster and controlled by angle than small trickle devices.

I would also look at something like a Lyman ammo checker. It is designed to drop a loaded round and/ or sized brass into to see it it is within spec. This will save you a lot of time and keep you from heading to the range with ammo that will not feed in the gun. With a hand gun, the old method was to pull out the barrel on a semi-auto and drop a round in or just check the rounds would fit in the revolver cylinder. If you are loading rifle, I like the steel single caliber checkers more.