Royals grow pretty fast no matter what. I think they would make nice potted palms and can probably be enjoyed in a pot for about 10-15 years from seed if you have high celings. I would give it a basic palm fertilizer, probably high in nitrogen, once a year. People say to give it 4 times a year in the tropics or subtropics, but then they grow really fast and will outgrow its pot in only a few years.

Royals love the heat so it should be brought outside every summer and taken in when temperatures dip in the 40s at night. They make decent indoor plants, but with any palm you have to watch out for spider mites which can be done by spraying the fronds with water every other day, and maybe mixing the water with a little soap every week or 2.

Good luck

It really depends on what size Roystonea you're talking about. I have just had smaller ones (under about 3.5 feet). As juveniles, I have found them to be somewhat slow growing, but as tropiczone says, they are said to increase their rate of growth as they mature. Not sure where the OP is located or whether the palm will be grown outdoors year-round or just in the warmer months. As indoor palms I would say they are moderately difficult/easy. I have had them have some issues with insect infestations (which were undetected by me because they were hidden in older leaf sheaths). All in all though, I would say that as an indoor or indoor/outdoor palm, they are probably better than the average Majesty palm. By the way, as adults, these palms get my vote for being the most stunningly attractive of palms in the world.

I live In Satellite Beach, FL on the Grand Canal off the Banana River. I have been growing Royal Palms, Foxtail Palms, and Teddy Bear Palms from seed for two years. My two year seedlings are now all about three feet high with three to four palm fronds and a base at the soil surface a little larger than the size of a government ball point pen. I recently planted three of the two year old, three gallon pots in the ground in my yard. When I took them out of the pots to plant, the roots had already formed a solid lattice along the bottom of the pot. In only three weeks, I observed an obvious advantage in the growth rate of the planted palms over the potted ones. More fronds and a much thicker base. My observation is the Royals will grow a lot more rapid and vigorously if planted in the ground over potted specimens.

Given what you say, I wonder if it would useful to put them in containers that are bigger than we would ordinarily use for most other palms. Container size does seem to matter to some plants (too big, too small, shallow, etc.) Based on what you say, I'll plant up my little ones sooner rather than later.