Metal Roof Rafter Construction

I need rafters built for a garage roof, which will be covered with metal roofing. There will be two dormers on the front and matching dormers on the back. 8' width on the dormers. I need to know the size of the rafters using menards I-Joists, and the size of the ridge board. Do I need a ridge board or beam. The walls are concrete ICF.

Requirements:
- Roof size: 42x38 feet
- Medium pitch (5/12 - 9/12)

Ideal Skills and Experience:
- Carpentry expertise
- Experience with metal roofing structures
- Knowledge of load-bearing calculations and rafter spacing

Please provide samples of previous work.