Go grab some plastic picnic knives from your favorite fast food place. The shape works much better than craft sticks for "buttering up" areas.
Tools of the trade. Small paper plate to mix and weigh the sealant. Craft stick to mix. Plastic knife to spread. The serrations on the knife act like a notched trowel and give you the perfect thickness of sealant.
I also really like using a veterinary syringe for laying down a nice consistent bead.
They can be bought from Amazon. I used the 100ml size. Let the sealant dry up inside, then you can pull the plug of sealant out easily and reuse several times.