In reply to stp:
Have got a LOT of space!
Planning a 6ft wide 8ft high 5ft deep section that leads into a roof thats 6ft wide and 6-7 ft deep. also have a space for another angled section that would be at a right angle to the first but leading to the same roof that can be 8ft wide but would be a lot shallower than the first as theres only 2.8ft to lead into the roof section on that side.
Maybe better to visualise it..
North wall: 6ft wide, 8 in height, 5ft space for angling that section
West wall: 8ft wide, 8 in height, only 2.8ft for play in the angle
East wall: Just going to be flat, can add a few volumes if needed and theres space to not smash into them.
Roof section: 6x7ft. 8ft high.
South wall. Might leave it open, potential crack machine, or maybe shallow stepped overhang.