Any of the allowed medium will be accepted if it is applied in the same manner that watercolor is applied, to include dry brush. However, if the paint is applied so thickly that it becomes raised in depth (globs of media) on the paper, it will not be accepted. The dry brush technique is a valid watercolor technique and is very acceptable when applied in the same manner as watercolor.
The dry brush technique can be achieved with any water-based media. Regardless of which water-based media is used, the brush should be dry or squeezed dry of all water, loaded with the aqueous, watercolor-consistency media, and applied to a dry support….or… the dry brush can be loaded with aqueous media and then squeezed dry. How much paint remains on the support when applied depends on the swiftness of the application; the dampness of the brush, and/or the dryness of the support. However, if globs of raised application of paint remain on the support, it will not be accepted.