I was taught that it's really only voltage that really needs to match to avoid damage. And even that can be a bit fuzzy with modern electronics and their charging circuitry.

The wattage and amperage only measures how fast the charger will recharge the battery. There will be a minimum amperage needed to power the laptop... but as long as you exceed the the minimum the laptop will run fine even if the adapter is capable of crazy high Amps. The laptop will only pull what is needed.