In reply to Blue Straggler:
> (In reply to marsbar)
>
> Do you tend to need to have two of the same model for this, or are zips standardised?
It's best, there's no standard material for the zip, let alone size.
Get the zip on the same side as you write with then you can always remember which side it's on. Unless you're ambidextrous. Then you need a tattoo.