One way to learn the dash vault is to transform your lazy vault into a dash vault. This should work well if you're comfortable with lazy vaults. So start with a lazy vault. Then try to bring your feet off the ground before placing your hands on the wall. This will be like a dash vault at an angle.
When you feel comfortable with that, try changing the angle until you can go straight at the wall. You may need to use more speed in order to get your legs out in front of you.
Remember to progress safely and only advance when you feel comfortable.
O.o I can't say I've ever heard of doing the dash vault at an angle until you feel comfortable going straight. Or using a thin bench as opposed to a picnic table. But to each his own, I guess.
IMHO, use the picnic table, because it is the perfect height, and there is more surface area for your hands to contact with. If you try it on a bench, or a wall of some kind, you could over- or under-shoot the obstacle if you're not prepared for it.
There's no exercises that will help you with this, per se. It's a skill, and if you want to get better at it, you just need to practice it. Ozzi's tutorial is a phenomenal one; it's how I learned. Repeat the part in the tut where he has you simply jump onto the table and kind of slide your feet out from under you into a sitting position after you land on it. Try to shoot for the furthest plank (assuming your table is wood).
Get into the habit of jumping
across the table rather than
over it. That is, focus on getting distance over the table as opposed to height; doing so will put your body closer to the top of the table, ready for your hands to come down and carry you through the vault.
Just practice the progression over and over, adding a little bit more speed and power behind your jump every once in a while, and you'll have it down in no time, trust me.
