There are multiple heating options for the ZipFit - depends on your tolerance for risk.
- Lowest risk - steam the shells only. Won't form the cuff or the tongue real well.
- Medium risk - steam the shells and microwave the liner (50% power for 2 minutes, pull the top strap). Much more thorough heating resulting in "stronger" forming
- Higher risk - heat the shells and the liners in an oven (convection is better, but standard will work) - this will help your shells adapt better to the liners and the plastic upper cuff of the liners will also form to your leg shape and the shells.
If you're interested in diving into any of the more advanced methods please PM me and I'll provide details.
The beauty of the ZipFit liners is that they're always adapting to your foot - so yes, skiing them is the ultimate final fit. That said, the OMfit material still needs that extra heat boost to get that initial fitting done. I don't think you'd ever get them all the way there without that process.