Jeff, I actually use four orchid formulations but those are usually used during the fall and winter months when everything is inside. During the spring and summer months I will use 20-20-20 Miracle Grow in an applicator that dissolves the powder and dilutes it as it sprays. Every third feeding will be a blooming fertilizer, something like Peter's. Orchid fertilizers by and large are simply too expensive to use in that spray applicator.
Keep in mind, when I water and when I fertilize, I am doing so not only with orchids but bromeliads, tillandsia, staghorns, ficus, plumeria, ginger, and whatever else I have potted up at the time. Even though I use Osmocote, I still supplement that with water-soluble fertilizations.