SECOND FLIGHT REPORT:
I bit the bullet and added the full 3/4 oz. tailweight, and moved the LO back about 1/4":
Much, much better; CG now about where the front LO was (and is again; reason following). Stability still OK; it will now perform round maneuvers pretty well--no square corners though! It does fly smoothly, very pretty lazy eights.
Still had quite an outward yaw, so I moved the LO back to their orig. position--now the CG and LO guides are in about the same place; when hanging by the leadouts it hangs level; yaw in flight is lessened but still there. I'm thinking I need to remove some or all of the rudder offset.
Interesting phenomenon: When the engine quits, the glide is flat and will not flair nor stretch. It lands where it wants to land. Not hard, but it refuses to raise the nose for a flair or for nursing a longer glide, even with full "up". I don't believe it is a balance issue, but something peculiar to canards. I'm not an aeronautical engineer, don't know the terminology, so the following will sound like I'm an ignoramus (come to think of it, I am an ignoramus so I guess that's all right):
In a standard planform, the elevator has lots and lots of leverage to raise the nose, sitting at the opposite end from the engine; in a canard (esp. the layout I'm using) it doesn't have nearly so much. In fact the mechanical advantage is negative, since "down" is "up"--it's not pushing the nose up by dropping the tail, but trying to lift it by itself. While the engine is running it's fine; perhaps prop blast helps, or perhaps just engine pull helps the elevator lift the nose. But on its own, deadstick, seems like the elev. becomes fairly ineffective. I guess the wing doesn't help pick up the nose nearly so much if at all. So I'm thinking, maybe a canard needs more elevator area to gain the leverage needed; or maybe my specific planform, with the engine in front of the stab/elev., exaggerates the problem.
My solution (experiment) is to rebuild the stab/elevator, same position, same shape, but with the hingeline 1/2" further forward--that will put the elevator that much closer to the weight (engine) it's trying to lift, as well as give it more area to work with. At the same time I may add just a skosh more tailweight to bring the CG back just a little more--as I said, it's still plenty stable and smooth, no twitchiness at all. Oh, and take out some rudder offset.
So what'chall think? Surgery is pending...