I think some defining is needed here...
Generally, the definitions are the angle of the throw, if any, based on the position of the gun station RELATIVE TO THE HANDLER.
So if handler is at home plate and gunner is at pitchers station throwing to the LEFT...
A FLAT throw: goes to THIRD BASE
An ANGLE BACK: goes to short stop
An ANGLE IN: goes 1/2 way between third base and home (so I suppose the dugout)
A straight in throw, which I've never used in training nor do I intend to (except maybe in the case of a diversion bird thrown on the dog's return from a mark), would go right toward home plate.
Then there are variations of angle back and angle in based on the size of the angle. So we say things like "sharp angle back" or "slight angle back" and so on.
We don't usually mess with the arc and distance of the throw except in some odd situation where the gun station and location of the bird landing dictate a shorter or longer throw. Otherwise, I personally prefer as high and long as possible. but an average of each if someone can't do a super duper throw. In training, I want the highest probability of giving the dog every opportunity to get a good mark, so I like really nice big throws if possible.
The only time I'll do a bird that's thrown fast with little arc is on a breaking bird where I really want to get a correction or if I want to blow their mind on a wiper bird. other than that, I like "normal" throws.
I think the above are the "generally accepted" definitions, although I may be wrong. So if you're using definitions other than the above, you may want to clarify so everyone isn't talking about something different.
-Kristie