HVAC Ductwork Design & Calculations

I'm seeking a professional to create detailed HVAC ductwork drawings and perform Manual J and D calculations for a new construction walkout basement two story single-family home with upstairs and separate downstairs system.

Key Requirements:
- Accurate ductwork drawings for new residential construction
- Manual J calculations for load determination
- Manual D calculations for duct design

Ideal Skills & Experience:
- Proven expertise in HVAC design for residential buildings
- Familiarity with industry standards and codes
- Proficiency in CAD software for drafting
- Strong attention to detail and accuracy

Please provide relevant work samples and a brief overview of your approach.