Realistically; visit three local gun shows, or visit 5 or 10 local major gun dealers. You will find at least one and probably more VH grade, 12 gauge, 30 inch barrel Parkers, with no dents in the barrels, no slivers in the stock, and no rust on the frame for a cost of $1000 to $2000 dollars. This is less than or comparable to several imported side by sides you may also see.
Pick the gun up; look at a bright light or other target on the ceiling; close your eyes; mount the gun; if it is pointed at the target when you open your eyes buy it.
Early VH guns are usually on the 2 frame and choked F and F, later guns are on the 1 11/2 frame and choked M and F. JD SHANK wins sporting clays tournaments with a Parker choked F and F, but we all don't shoot like JD, You may wish to open at least one barrel of an F and F gun. M and F isn't really a handicap; I shot a 21 and a 22 at skeet with a two frame M and F Parker about three hours ago.
Measure the chambers; there is about a 2 to 1 chance that they will be 2 5/8 inches. Have a good gunsmith stretch them to 2 3/4. If he does a good job, no one will know.
At this point you will have about 1500 to 2000 dollars invested in a gun that will ingest any commercial ammunition with out retching, and will not be a handicap in any side by side tournament you may enter. Buy or load about ten flats of ammunition, and you will have a very pleasant experience learning to shoot it.
Everyone shoots his own style; my only recommendation is shoot with the forearm laying on your palm with the index finger aligned with the barrels.