The underlying height and setback regulations shall apply, except as modified in this Section, inclusive. All height shall be measured from curb level.

1. Street wall location
   
   For zoning lots with wide street frontage, the street wall provisions of paragraph (a) of Section 35-631 shall apply.
   
   For zoning lots with narrow street frontage, the street wall provisions of paragraph (a) of Section 23-431 shall apply and extend along the entire narrow street frontage of the zoning lot.
2. Building height
   
   Within 100 feet of a wide street, the underlying height and setback regulations applicable to an R7A District shall apply. Beyond 100 feet of a wide street the underlying height and setback regulations applicable to an R8B District shall apply, except that the maximum base height set forth in Section 23-432 (Height and setback requirements) shall be modified to be 66 feet.
3. The City Planning Commission, by special permit, may modify the special height and setback regulations set forth in this Section. In order to grant such special permit, the Commission shall find that the distribution of bulk permits adequate access of light and air to surrounding streets and properties and that the maximum height does not exceed 99 feet beyond 100 feet of a wide street, and 115 feet within 100 feet of a wide street.
   
   In conjunction with such height and setback modifications, the Commission may allow modifications to other applicable bulk regulations of this Resolution. except floor area ratio regulations, for a building developed or enlarged using public funding, as defined in Section 27-111 (General definitions), to support residences with rents restricted pursuant to a regulatory agreement with a City, State, or Federal agency, provided that such building is located on a zoning lot that has an area of at least 40,000 square feet, occupies the frontage of a wide street, and contains a mass transit or water supply support facility. In order to grant such special permit, the Commission shall find that:
   1. there are physical conditions, including the presence of existing buildings or other structures, public infrastructure, or topographical features, that create practical difficulties in complying with the bulk regulations that would adversely affect the building configuration or site plan;
   2. the proposed modifications will not unduly obstruct access to light and air to adjoining properties or streets;
   3. the proposed scale and placement of the development or enlargement relates harmoniously with the surrounding area; and
   4. the requested modification is reasonable in relation to the practical difficulties on the site or the public benefit derived from the development or enlargement.

The Commission may prescribe appropriate conditions and safeguards to protect and minimize any adverse effects on the character of the surrounding area.