When I started sporting clays, the most common choke used was Modified. Several years later screw in chokes became more available and people began swapping out chokes. Several years after that the trend was back toward fixed chokes, generally Improved Modified in fixed barrel guns and IM/Full or Full/Full, at least for the better shooters.
The theory is, (generally speaking) the center of the pattern is the same regardless of choking and if you put the center of the pattern on the clay, choke doesn't matter. Years back Bruce Buck discussed this in his "Ask the Technoid" column in one of th shotgun magazines and online.
Tighter chokes will break just as many targets up close as more open ones as well as provide a denser core at the longer ranges. Not having to concern one's self with choke choice means one can spend more mental energy making the shot than wondering if the "right" choke is being used. Until one realizes this, more open chokes are preferred as it gives the shooter more confidence in making the shot- whether deserved or not. If you are used to shooting a Full choke, use that and don't give it further thought. Just concentrate on the bird and shoot when things look right.
As for shells, most anything one can buy in 7 1/2 or 8 will be as good as the shooter if not better. I highly doubt anyone here is good enough to notice a difference in the shells used and even if one is in the upper 1%, their shooting ability will offset any deficiency in she'll quality to a large percentage. Premium loads will do more to soothe the shooter's mind than actually improve their ability. I'll shoot them to get the hulls for reloading but won't but won't worry if I have to settle for inexpensive Federal, Winchester, or Remington 100 packs or similar quality shells for all but FITASC, Super Sporting, or Compak where the ranges tend to be greater. Even then, it is more to ease my mind as I am not in the upper crust of shooters.
