#1
Hey, newbie to the fourm...
Been playing guitar for a while.
And skimmed through the rules and stuff.
Mostly I'm assuming don't be annoying.

Anyway, I'm practicing hammer ons right now, and I'm using the hammer on from nowhere as a strength builder, but for whatever reason, I can never get the "hammer on from nowhere" anywhere near the volume of a picked note.

But I've seen this guy play the best hammer on tune in the world

http://www.youtube.com/watch?v=saC7G0JkVPw (You should listen.)

And then in his tutorial, it shows he is hammering on from nowhere.

http://www.youtube.com/watch?v=DuJwlsjfh6M (skip to 30 seconds in)

My first question: I have a steel acoustic, and an electric. (nothing special) I'm attempting this on an acoustic, but like a lot of other things, this technique's harder on the acoustic than on the electric. Is the hammer on from nowhere technique, and getting it at the right volume, like the bending technique in that while it is possible on a steel acoustic, it's ridiculous to try, or is it possible?

My second question: I've been told to practice legato by putting it into a small concise motion, less than a centimeter away from the fretboard, and try to get it to the right volume. Especially by Guthrie Govan in his creative guitar 2 book (really good book), but when he does it here, he's putting his a finger a good distance away before hammering.

http://www.youtube.com/watch?v=ZF7LD46o13c

The best hammer on tune in the world guy does the same thing.

So I know this concise motion thing is a guideline, but when I'm actually playing a song, should I still be sticking to that "less than a centimeter" away from the fretboard principle? Does it really take time from finger strength to develop until it gets a good volume?
(I'm pretty obsessive of this stuff...)
#2
About hammer-ons from nowhere. Yes, it's completely possible to get good volume from them on an acoustic. It takes practice and you have to develop your finger strength. It will take time, you won't master it in a day. Just make sure your technique is good and you're not having so much tension in your hand from trying to mash the string. A fast and accurate hammer-on will sound much louder and pleasing to the ear than just thumping the string as hard as you can.

About legato. Yes, in theory, you should keep your fingers close to the fretboard because of the economy of motion. The farther you move your finger away from the fretboard, the farther you have to move it back to get to the strings. As long as you keep your idle fingers relaxed, they will naturally stay close enough to the fretboard. Don't stress too much about it, but you definitely should practice keeping them close. It's a hard habit to break down the road.
#3
Smaller motions are better. Watch Holdsworth play.

Apart from that, loud hammerons from nowhere take finger strength and excellent accuracy, the latter being slightly more important and both taking plenty of practice, although a lot more with acoustic guitars.