Principal uses, other than single-family dwellings (including permitted conditional uses) shall meet the specific lot area, yard. setback and other regulations provided for them in the regulations for the involved zoning district, Otherwise, they shall meet the requirements of this schedule set forth above for residential uses based on the following(a) Where the minimum lot area for the involved nonresidential use is three (3) acres or less, the above requirements for the R-3 District shall apply

(b) Where the minimum lot area for the involved nonresidential use is greater than three (3) acres, the above requirements for the R-5 District shall apply [Amended 9-15-87 by Ord. No. 1987-9]