User account to run WSUS under

I logged onto my SBS machine as a domain admin and installed WSUS 3.0.
Everything works, but there's just this one problem - WSUS services, and the
way it accesses my SQL Server instance are done using my domain admin
credentials. I would like to restrict WSUS so that it uses less privileged
credentials.

Can I install WSUS 3.0 by logging onto my SBS machine as a local admin?

And why couldn't Microsoft let us specify a less privileged domain user
account while installing WSUS 3.0? I guess we should feel privileged at this
time that we can at least specify the SQL Server instance it goes against.

Thanks.

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