Lists of professional freelance researchers for each province are given, with contact details, on the NARS (National Archives of South Africa) website.
Note that these details are not regularly updated as they should be.
If you decide to delegate to a local SA researcher, it speeds things up if you’ve done your homework first and are able to provide full source references from NAAIRS, copying and pasting these from the Results Details (not Results Summary) section of the index.
If you haven’t been able to find a relevant reference to your ancestor on NAAIRS try to give the researcher a reasonable amount of family history detail as a starting point: not your entire family tree going back to William the Norman, but somewhere between that extreme and minimal information.
Questions to ask (other than the important matter of costs and preferred method of payment) include whether the researcher will provide information as transcripts or as digital image files. Photocopying – on a flatbed copier – is not permitted in deceased estate material, and is in any case often impossible due to the size and binding of older volumes.
For preservation reasons, access may be denied to files (of any type, not only deceased estate files) which are in a fragile condition. So, don’t shoot the messenger if a researcher reports that a required file cannot be ordered.