Mismatched panels?

I'm short six 400 watt panels to complete our 25 kW off-grid installation... can I use four 600 watt panels in place of six 400 watt panels? These would be in series on the same string.

I understand there may be a loss of efficiency, but this will be a temporary fix while I wait a couple of months for the permanent 400 watt panels to arrive.

TIA for any experience and guidance.