Other than a handful of rarer staghorns, I grow staghorns to sell, so what I do is not what you would do. Though I am simply a hobbyist grower, I do have a lot of tropical plants, 500+ orchids and 300+ other tropical plants. Having that many plants to deal with forces me to water/fertilizer almost every single day.
Oddly enough, just like you, during the warm months (March/April through October), practically all my plants are under large oaks and cedar trees, staghorns included. When I give lectures, I tell folks that the smaller the staghorn, they more attention it will need. As you well know, once a staghorn gets up in size, those layers-upon-layers of basal fronds tend to function as a sponge, holding water/fertilizer for many days. The small ones don't have any basal fronds to speak of, and thus, more frequent watering/fertilization is necessary. When my plants are outside, and the highs are less than 90 F, I just hose all my plants down every 2-3 days. If the weather is really hot, 90 F or higher, they would get hosed down every 1-2 days. Again, since I am fertilizing a lot, I will fertilize those staghorns every 1-2 weeks. I am using a hose-end applicator and my fertilizer rate would be between 1/4 and 1/2 tsp. per gallon.
Do you take the staghorns north with you in the summer or does someone care for them?