As far as may be practicable and not in conflict with any statute of the United States or the rules or regulations of any agency thereof which may assist in financing any project undertaken pursuant to this chapter, the Public Service Authority shall use and give preference to South Carolina workmen and South Carolina materials. As far as may be practicable, and not to conflict with any rules of the United States Government or any agency thereof which may assist in financing the development herein proposed, the Public Service Authority shall use South Carolina materials and shall make purchases within the State where possible. As far as may be practicable, the labor to be employed on the development herein provided for shall be resident South Carolina workmen, and the same shall be allocated to each county in the State ratably, as the need for employment may exist, and, as far as may be practicable, as reflected by the rolls of the unemployed in the various public employment offices in each county in South Carolina.