I've had the screwdriver in my hand, disc screws loosened, and just stopped. I had no idea which way to move it or by how much, and I'd never actually looked at what it was set to.
The numbers are easy to find. A little wider than shoulder width, front foot around 12 degrees, back foot around minus 6. Front positive and back negative is what people call a duck stance, and that's exactly what I put in at the start. I rode it for a while and there was nothing wrong with it, but it never turned into my board.
【Width is settled on the floor】
Width you can work out before you ever step on the board.
Put your feet about shoulder width apart, crouch down, and see what happens. If your knees start falling inward or the outside of your thighs strains, it's too wide. If your hips won't drop and you feel cramped, it's too narrow. Whatever width lets you get low easily on the floor is the width that lets you get low on snow. Wider looks more stable, but widen it too far and your knees stop bending, which left me riding upright the whole way down.
If you ride ground tricks, pull it in slightly from there. You get more distance between the binding and the end of the board, so the pop comes back harder when you load it, and ollie height depends far more on this than on your angles.
【Angles follow what you want to ride】
The more you open the front foot, the more your body faces down the hill, which makes it easier to look ahead through a carve.
If you ride ground tricks, keep the back foot negative. You'll end up riding switch sooner or later, and when your knees move the same way in both directions nothing falls apart mid-trick when the board swaps ends. Start somewhere around 12 and minus 6, and if switch feels cramped just take the back foot further negative.
My bindings are Burton, and the disc moves in three-degree steps, so dialing it in one degree at a time was never an option. Even then, three degrees can feel like a different board, and I spent a long stretch riding duck, nudging it over, riding again. It took me a good while to settle.
Rather than working around the four screws in order, go across in diagonal pairs and bring them down a little at a time. Drive one side home first and the disc can end up fixed at a tilt. Vibration also works them loose as you ride, so it's worth going around once more at the end of the first day on them.
Later on I wanted to carve, and everything I read pointed to a forward stance. The back foot comes off negative and swings positive, the same direction as the front. I ride 30 and 18 now, and it's a completely different machine from the duck setup.
On a day that's mostly carving with a bit of ground trick thrown in, I just leave it forward. If I want a day of nothing but ground tricks I'll swap back to duck, but that happens maybe once or twice a year.
The angle that suits you does shift with what you're doing, but change it over and over through the season and everything stays half-learned until spring. Most of the time you already know what you're chasing, and staying put gets you there faster. I've settled on carving, so I ride forward and do my ground tricks that way too.
Write the numbers down whenever you change something and you can always get back.
Once you know the width where you can crouch lowest and what you've decided to chase that season, the numbers tend to follow on their own.