Steve is the handstand guru. Listen to every word he says. It will help better than anything, I promise.
Re: the hands...
in yoga there is a concept known as the "index root" which is basically the knuckle where your index finger meets your hand. In inverted poses and handstands this is where your body should "root" through the hand. I actually imagine a root growing out of my hand at that point, gripping me to the ground, when I do a handstand.
For handstands you need to work on strength and also proprioception for balance. Some people are better in one half of this equation than the other; the important thing is to figure out if your problem is a strength issue, a balance issue, or both. I am still working on the strength to hold a handstand. I can find my center of balance easily enough, but my arms start to tire quickly and then I get wobbly and lose my balance.
Re: abs...
Situps are not a good way to develop strength in the abdominals. They can be a good start, but they are incomplete and don't really train all the abs, nor do they train the abs to work in unison to accomplish physical tasks.
More to say on this but my incredibly naughty pizza is here and I'm starving.
