IMO, there is no better choice than an A.H. Fox Sterlingworth for your first SxS. I have a modest accumulation of American doubles and they are by far my favorites. That said, if you are new to them, having someone who is educated in their nuances and "limitations" to guide you through your first purchase will be a great benefit to you. I won't volunteer his name but there is a member here who is fairly well versed in them. He is within an hours drive of you. I only know him through this and a few other sites but my opinion is he is a stand up fellow and would probably be willing to help you out. Hopefully he'll post soon.
The Fox website is a good source to start your education. https://www.foxcollectors.com
Keep in mind you are not dealing with a modern gun. Amongst those who deal with older doubles, there is an adage that you "buy the barrels". Most anything else can be fixed but if the barrels aren't sound, walk away from the purchase. If unaltered, the chambers will be short (2 1/2", 2 9/16" or 2 5/8" depending on gauge) on earlier guns. The stocks typically have more drop than most shooters today are accustomed to. The Fox action is very strong but most of us who shoot them choose to use lower pressure loads (reloaded or those such as sold by companies like RST RSTShells
). You're dealing with wood that is either pushing or over 100 years old. A steady diet of heavy loads can be detrimental to old stocks. Others may say different, but the barrels are not compatible with steel/HeviShot loads. Lead, Bismuth, Tungsten-Matrix and the like are what you'll want to use. As far as the chokes you mentioned, sounds pretty typical. Most likely they were "measured" using a drop-in gauge which doesn't tell the real constrictions. To find the true numbers, a bore gauge is needed but that only tells you the difference between the bore and the choke. Paper patterning will tell the whole story as different loads will pattern differently.
Best of luck in your decision. They're great guns.