You will need to shoot both chokes with as many different kinds of ammuntion as you can afford at the range you intend to shoot. Your shotgun will show a preference for at least one load.
Either a full choke,or extra full choke shotgun barrel.
Yes.
Unless the manufacturer specifically says you can't, call them first.
You would use a full,or extra full choke if using 00buck for hunting purposes.If for self protection thats up to you.
Is it a screw in choke?
Either modified or full choke... full choke keeps the shot in a tighter bunch, so it is better for a longer shot.
Most ARE shot from full choke- or even Extra Full Choke.
Yes, you can fire buck thru any type choke. However this does not mean it will work better, as smaller shots do. It is very easy to over-choke buckshot. Most smaller shot does not have as much of a problem as with 00 buck. As the shot goes through the choke "if too tight" the shot smashes into each other and the barrel and deforms the round shot, with flat edges. This can give you a "card" reaction. If you flip a card through the air you will see it doesn't fly straight but flips all over. This is what happens to over-chocked 00 to a lesser extent. Some chokes are even dangerous with 00 buck. Take a 90% Turkey choke. This could blow the end of your barrel off. Talk to every manufacture out there and they will tell you modified choke is recommended for 00. With smaller buck you may be able to tighten up a bit.. but you will not get a better pattern. At 50 yards on a modified choke with 00 you will get 1 or 2 pellets. Smaller shot will grant more.
That will depend on whether the choke tube is rated for steel shot or not.
Full choke for all buck shot.
That will depend on whether the choke tube is rated for steel shot or not.
You can use steel shot with a choke anywhere from cylinder to modified, i wouldn't recommend using steel with a improved modified or a full choke.