Can Estates be reloaded?
In a nutshell, yes they can - basically ANY hull CAN be reloaded. The question becomes can it be reloaded SAFELY with a TESTED recipe? In many cases, the answer is no. There will be folks who say that it doesn't matter as long as you follow the recipe for a similarly built hull (straight versus taper, etc); however, I like my fingers and eyes, so I use known recipes from a good resource like the aforementioned Lyman manual or from the powder mfg. websites
While there IS some interchangeability between certain components - certain primers are equal strength, certain hulls from the same company are interchangeable, and certain powders will use the same recipe, until you get well-versed in all of the little nuances involved, do yourself a favor and stick to the main names, even if they cost a little more where you live. Once you've built some safe loads, and are happy with their performance in YOUR gun, then start to work on others for different applications.
I can tell you what works in MY gun, and it might do a decent job in your gun, then again, it might not be as good as something different. Even though these do not have match chambers and throats and specific rifling, etc. like a rifle, they are unique unto themselves in many ways.
One thing I would recommend when trying to build a good load for your gun - load no more than 2 boxes of that load at first. Take the first box to the pattern board and see how it performs on paper and take the second box to the skeet field and see how they perform at station 1 and 7 and maybe 4. If the patterns seem iffy, but you are crushing targets, you might want to leave it alone. If it is the other way around, you might need to look at gun mount or tweaking the load just a little.
The main thing is SAFETY FIRST AND FOREMOST - fun will follow