In a double, where two constrictions are available, improved cylinder and modified are a good pairing, especially in fixed-choke guns. If screw-in chokes are an option, try a more forgiving match, like skeet and light modified. Shoot the more open barrel first on the covey rise, then the tighter barrel as the birds make their escape.
The CD and DVD have a single track of data in the form of a spiral, which starts as the center going outwards. The data is stored on the bumps or pits which are then read by the CD/DVD layer. The bumps/pits on a DVD are much smaller than on CD, allowing the DVD to store more data.
A Data DVD is not a DVD Video; it will not play in a set top DVD player. Data DVDs work just like a CD-Rom. They are a storage medium for storing files just like a CD. The only difference is they hold more information than a CD would. Data DVDs work with computers like CD-Roms do. However your computer needs to have a DVD-Rom disk drive to read our Data DVDs.