Major Boddiker's Crit'r Call Standard size. It is about as good of a production call as has ever been made. There is a reason a lot of government hunters/trappers use it. It works! I've killed quite a few coyotes using it and I'm sure that I will continue to.
The only thing I do different is I actually use it as a young coyote howler and open most of my stands with a young coyote howl. Then wait a couple minutes and go into either a prey in distress like a deer or rabbit. This time of year however, often just howling works. I also sometimes skip the prey in distress and go straight into pup in distress.
An open reed call is what I recommend, everyone has a favorite and they all work some of the time, no call works all of the time.
As far as how to call, I never use howls if I'm expecting a bobcat or fox to come in. If I'm only after coyotes a howl usually doesn't hurt. The best results with howls come when the coyotes are already howling and you howl back at them. After a while you will learn what some of the different barks and howls mean to the coyotes but, when in doubt, call back using THE SAME TYPE OF HOWL AS THE COYOTE. Howls also work best after dark.
If you want to stop a coyote you've spooked, or you call in a double and shoot one but the other starts running, the sound of a yelping dog also called a "kaiyai" call will often cause them to stop and look back.
Unless you really understand coyote vocalizations, I would take it easy on the howling. Certain times of the year it can be awesome.
Agree with the open reed calls being the way to go for year round use, however, I also like to use a couple odd ball closed that sound a little different than what everyone else is using. Primos Randy Anderson cat nip can sound like so many different things, same with Zepps rattler.
When using the fox pro, I use a lot of bird sounds, instead of the same lightning jack everyone else has been playing the coyotes entire life.
Don't think there is a right answer to the call sequence, experiment a bit.
I think the little dog by promos is the best $22 you can spend. It comes with a green reed, a white reed, and a horn. With these three items I can make just about any sound I want.
I've even used the white reed as an elk Cow call. It takes practice. I used to drive a ton for my job and I'd spend hours on the car practicing. Good thing I was alone. I'm no champion caller but I have enough confidence in the noises I make that if I have the wind in my favor, and have the right setup visibility wise I almost count on calling one in.