Hi Rockm - sounds like we're neighbors (I'm in Arlington near Falls Church). I just looked at google satellite maps and my fears are correct - my location would face due south with a slight tilt to the east.
120 degrees is pretty scary, but doesn't surprise me. I know how cooked I feel after an afternoon of golf in July
I'm just starting out, but have some maples, pines, elms, junipers, etc. that I've collected and plan to work on in the spring. I figure setting up a bench or a shelving unit would be a good winter project in the meantime. The shelving unit I'm thinking about is part of the Gorm collection at Ikea - one of the units has a 110 lb capacity, so I think I would be ok for a little while at least.
Do you mind me asking what grade shade cloth you are using?
Thanks very much for your thoughts.