I would imagine there are a lot of issues to consider…
Are you going to give him all the older homes and crawlspaces? If so the pay had better be good if you want him to actually do the job.
Are you going to make him pay for his misses/complaints?
If not, don’t expect him to be thorough, (he only works there).
You might only get what you pay for, I know this has been a problem around here as many of my clients have been burned on some past inspections where there was an employee inspector. I hear court cases are very common around here for the multi-inspector companies.
Another thing it depends on is whether you’re covering his E&O or he is buying his own. I know quite a few multi inspector firms locally and have talked to the owners a lot, most of them pay the inspectors 60-80% depending on their experience. Make sure they are putting all your information on their reports.