How crooked are they? If they're just a bit off you should be fine:

1. Back off the screws
2. Insert boot into both toe and heel pieces
3. Does the boot fit? If so, tighten the front 2 screws...

That's a good point - I usually eyeball that the compass is coming off the edge at 90degrees relative to the centreline of the ski. I lay down masking tape and scribe a pencil mark that is roughly...

I really like this method - it's quick, accurate, and no measuring required.

The only think I'd add is that I use a pencil compass/scriber to lay down the marks on my ski. Not sure how you'd...