@Dysfnal dont use the PDP, the thing with headshots is that its high risk high reward. the PDP only does 90 headshot damage, so it turns into high risk low reward. not to mention it will throw your timing off with bodyshotting when you go the FEL-IX again.
Maps i recommend are Trainyard, Bridge, and Chapel, the rest of the maps are also maps where you can be a good sniper, but you need to be more experienced to be really effective. Bridge phase 3 is also in that area, but stages 1 and 2 arent.
Defense or Offense doesnt matter, but they differ in what you can train. Defense is good to train holding angles, finding new angles, and headshotting people that are running around/running out of their spawn. examples are shooting people crossing the street to the red van in bridge 1st OBJ when you are on the attacking side, and shooting people crossing the canal from the attacker spawn on trainyard defense. In offense you can train how to break into enemy area’s, and learn how to pre-aim them. i just uploaded a sniper montage (coincidentally for you it only has felix aimee clips). ill tag you in the thread ill make to give you an example.