*activates sharingan*
*I copy the neccesery handseals. Then I'm concentrating my Raiton chakra in my right hand. When I have gathered enough I blast a hound shaped stream of lighting from my hand*
(in the description of the jutsu it's said that the lighting remains attached to my hand... does that means I can manipulate to go wherever I want to? also does it remains on the battleground for the next turns??)
well lets look at it this way, just because it stays attached to your hand you can't keep it forever, you can't direct it around attacks either really imo, and yes it stays attached to your hand so you can manipulate it... however an attack is just an attack, you don't keep water dragon more than one turn and that's animated water basically, and would you really want to keep control of the dog preventing use of other jutsu while you use it.
also if you use sharingan to copy jutsu i won't train you at all, it's as simple as that... i won't let you train easier and quicker just because you have a different KG to someone else. that wouldn't be fair on others who spend much longer training.