jabiman (and others)
I think you will find company culture / policy, and regulator oversight, a better judge of relative safety i.e. you do not need to see the individual crews' experience - which anyway is a small sample / rather subjective. Instead look at the record of an airline / nationality, which to an extent some areas do anyway (the EU "banned" list).
If you do wish to persist in measuring safety by hours, I presume you would rather a 5000+hr F/O to a 500hr one? I might suggest that rather than a straight "yes", a better question might be "if (s)he has 5000+hrs, why are they an F/O"? There are plenty of good reasons - an employer might have a slow promotion process (typical in the 'majors'), the individual might have had a fair degree of bad luck, or just personal circumstances changing employers or whatever. But there are also some specific reasons which might mean your criteria is flawed...
NoD