my wife uses the same gun to shoot clay at the farm, Ive found the imp cyl to be best
if its an overcast day and we can see clearly I will screw in the full choke and go for longer shots...
Good point ... some folks refer to clay targets simply as "skeet", even when they are talking about shooting clay targets informally, say when they are thrown from a hand trap or stationary trap set-up.
Skeet is a particular clay target shotgun game, as is Trap, Sporting Clays,
5-Stand, etc., etc. Clay targets are used in all those games, but the clay targets themselves... or "clay pigeons" as they are sometimes called... are not skeet.
Improved Cylinder Choke (sometimes called 1/4 choke, IC or Imp/Cyl.) has relatively little constriction, offering the largest amount of shot spread (of the 3 chokes mentioned in the original post ) at any given distance. It is typically used effectively on clay targets or game out to about 25 yards. Full choke on the other hand has a relatively high amount of choke constriction, useful on clay targets out to 40 yards or better ... maximum shotgun range. Modified ( or 1/2 choke) is pretty much in the middle of the two - between Improved Cylinder & Full (constriction wise) , and tends to work best on targets or game in the mid-range, 25 to 35 yard range.
Chokes can range from "Spreader" tubes, through Cylinder, Skeet or Skeet 1,
Skeet 2 ( sometimes called Skeet In & Skeet Out respectively), Improved Cylinder, Light Modified, Modified, Improved Modified, Light Full, Full and Extra Full. Turkey chokes for use with heavy loads of large shot and Predator chokes for use with buckshot have even more constriction still, and may be referred to as Super Full, Super Extra Full or some such. With standard lead clay target shells, they rarely provide ultra-tight patterns however.
Perhaps the foregoing will help understand choke a little more ?