You can smooth the process by helping to locate a suitable tenant. After that, you are looking to know which side of the equation the broker represents. If you get someone who represents just users, it gives them a completely unbiased and objective viewpoint of the marketplace and allows the user to know there is no conflict of interest. You need to create a strategic facility plan. That can start on the back of an envelope and eventually end with someone who has expertise in these areas, but there should be some formal process for thinking it through.
Rules of thumb depend on the user groups.
To a great degree it will depend on your business plan. Triple-net means you will pay for everything that occurs. That will include the real estate taxes, the utilities, the cost of managing the building, plus the cost of servicing the building, the insurance on the property, the security on the property. Most owners are not interested in having 15 tenants each doing their own thing. It creates too much confusion.