Staghorns don't really need a lot of care. Moisture is a far greater problem than dryness when it comes to staghorn ferns, but I understand your problem with limited moblity. Staghorns grow attached to trees in nature, so mounting them is the more "natural" way to grow them. Water quickly drains from mounted plants.
I grow mine from very small plants, grown on what are called plugs. I get my plants when the fronds are perhaps 1-2" long. I do pot up my plugs when I get them and use 1/3 general potting mix (sold at any big-box store), 1/3 coarse perlite, and 1/3 peat. I want a mix that does hold moisture yet allow for good drainage. You should allow the mix to dry out down to about 1" deep before rewatering. Do not allow your pot to sit in a water-filled saucer. Staghorns don't like "wet feet".
When my plants get fronds approximately 6-8" long, and perhaps have formed the basal frond, they all are mounted. That's what I sell - mounted stags.
I would suggest a couple of variations that may give you a better performing plant. One trick is to lay the pot on its side. This will allow the fronds to naturally arch downward, as they grow in nature. This trick also prevents, to a great extent, over-watering.
Another way to grow it is in a basket, hung from the ceiling or some other way. This is the way to grow a big staghorn. You can line the basket with coconut fiber matting, and this matting can also be found in big-box stores, or just purchase the basket with lining already put together. Use the same potting mix formula. The downside is the water will drain quickly through the potting mix and onto whatever surface is beneath the basket. That can be messy. Putting the basket in a sink and watering it there, allowing all the water to drain, will eliminate the mess but is a chore you might not be able to do.
When my staghorns are inside (keep in mind they will all be mounted), I mist them every week or so. These are epiphytes and are tropical, so they need humidity. I water my staghorns with 1/2 strength, general purpose fertilizer, something like Miracle-Gro is fine. They are fertilized every other month from October through February, and then once a month March through September.
