Question about antennas HF

[beorn]

I understand they are directional along the length of the wire but I was wondering some things like are these antennas meant to be horizontal or are they adjusted depending on the stations you are trying to contact? There are so many different antenna configurations. You need to pick one that is easy to install at your site. Also look at Flagpole Antennas. They are vertical dipoles with omni-directional radiation patterns.
Is there a best direction to face these antennas for most contacts IE North South East or West. A horizontal dipole radiates most energy perpendicular to the wire. In other words, very little radiation off the ends so to get most radiation going east and west you want to point the ends of the wires north and south.
Will a sagging wire cause problems? It depends on the sag but all antennas will sag if they are roughly horizontal. Read about "inverted vee" antenna.
Im halfway up the western slope of a mountain  does that mean that eastern contacts will be very difficult? Your antenna performance has a lot to do with this. It is a bit hard to predict.
How high above ground is ideal?  Here is a good website describing height.  https://www.qsl.net/aa3rl/ant2.html 
Let us know if you have more questions and good luck with your exam!Ken

[beorn]

Just getting back to this Im pretty set on a long wire antenna of 40 meters if I understand things correctly this will give me options on multiple bands. SW should give me best performance toward Reno and Sacramento, San Fran. South will give me best performance to Vegas and San Diego. I will probably set up both as I have the room. My question is will the radiating end of the long wire being lower than the feed point cause performance problems? I can put up a larger end tower if need be but would like to avoid if possible.

I have done some research and I do think I will be setting up a true long wire at 10m meters band but it will probably have different characterisicts with propagation in other bands.