Residential HVAC Engineering Design for Custom Home Remodel

I am doing a complete renovation of my approximately 2,700 sq ft home in Southern California. The house has been taken down to the studs, giving complete flexibility for HVAC design, duct routing, equipment selection, zoning, and diffuser placement. I am looking for an experienced HVAC engineer or residential HVAC designer to produce a complete engineered HVAC design package. I will use the design to install much of the ductwork myself, followed by a licensed HVAC contractor for equipment installation, startup, refrigerant charging, commissioning, and balancing. Please provide: Manual J, S and D Complete air distribution design (Manual T or equivalent) Equipment recommendations Complete diffuser and return selection Complete duct layout suitable for construction Home Information Approximately 2,700 sq ft Two-stories Conventional framing (no roof trusses) Low-pitch roof (2:12) Southern California climate New windows New insulation New drywall Improved air sealing All new ductwork Primary goals: Extremely quiet HVAC operation No noticeable drafts while sitting or lying in bed Low air velocities Excellent room-to-room temperature consistency Low static pressure duct design I would prefer additional diffusers operating at lower airflow rather than fewer diffusers operating at high velocity. Existing Comfort Issues: The home has significantly different heating and cooling loads: Upstairs experiences high solar gain due to extensive front-facing glazing. Downstairs remains considerably cooler during winter. The design should address these differing loads. Zoning Evaluation: There are 3 main areas of the house that I believe should be zoned separately: 1 – Downstairs bedrooms 2 – Upstairs bedrooms 3 – Upstairs living room, dining room, kitchen, and family room Air Distribution Please specify: Supply diffuser locations Return locations Airflow (CFM) for every room Throw Spread Drop Neck size NC (Noise Criteria) I am interested in architectural linear slot and plaque diffusers. Please recommend whichever is most appropriate for each room. Ductwork I intend to install the ductwork myself. Please provide: Main trunk sizing Branch duct sizing Round vs. rectangular recommendations Manual balancing damper locations Return duct sizing Complete duct layout Static pressure calculations Kitchen will utilize an induction cooktop. Please recommend: Makeup air requirements Preferred makeup air strategy Deliverables Please include: Manual J report Manual S report Manual D report Air distribution design Equipment schedule Room-by-room airflow schedule Duct sizing schedule Diffuser schedule Register schedule Return grille schedule Static pressure calculations Recommended equipment Zoning layout Please Include in Your Proposal Your experience designing custom residential HVAC systems. Examples of previous Manual J/D projects (redacted is fine). Whether you perform Manual T or equivalent diffuser selection. Whether revisions are included. Whether you are available for a video meeting to review the design. Your estimated timeline. Your fixed-price quote.