: The frame will weigh several pounds heavier than a lighter wood.

If it's only on the order of 5 or so pounds I can live with it. I ran into a web site yesterday that gave wood weights in pounds per board foot - I think white cedar was 2, white pine 2.2, Sitka spruce 2.4 and doug fir 2.6 . At those numbers, a length of doug fir weighs 30% more than it would of cedar (or 30 pounds of white cedar turns into 39 pounds of doug fir). Of course, those numbers will vary dramatically from log to log as you pointed out.

: Coastal doug fir is quite heavy ,

I live in NY state so I doubt that it's coastal doug fir. I think I'm going to go with the wood I have - I dug out my receipt and it states "No Returns".