No, unfortunately we can’t do that easily.
Also a facecount percentage setting would be cool because I find myself often converting various objects at once in proxies and they got different polycounts, and if I had a way of saying “facecount for preview = 25% of basemesh” it would be really cool.This is already done for the next service pack - there’s a percentage, plus min and max setting.
Best regards,
Vlado