In R9 or R10 Districts, for buildings that do not meet the criteria set forth in paragraphs (b)(1) and (b)(2) of Section 23-441, a tower may penetrate a sky exposure plane provided that such tower:

1. does not occupy more than 40 percent of the lot area of a zoning lot for zoning lots with a lot area greater than 20,000 square feet, or more than 50 percent of the lot area for all other zoning lots; and 
2. is set back at least 10 feet from a street line along a wide street and at least 15 feet from a street line along a narrow street. 

However, the provisions of this Section shall not apply to any building located wholly or partly in a Residence District, that is within 100 feet of a public park with an area of one acre or more, or a street line opposite such a public park.