"I am concerned about the first repair presented, though, and recognizing you undoubtedly had to edit a bunch out for brevity: it's very tempting to bondo a crack, but for a structural repair one would need to grind out........."Exactly right.
Most of the pictures seen were grab shots taken during the work ...when
I remembered to grab one. What is not seen enough in the slide show is the fiberglass reinforcement I did on the underside of cracks, plus grinding and getting to green to insure maximum topside tooth. I slathered fiberglass mud and cloth patches under the shell, insuring a wide but hidden patch would bridge the cracks. After that was set, topcoats of fiberglass closed all gaps.
Also not recorded was the bone-ugly patch job by the previous owner, which I first had to clean out. The guy had good intentions, but high on silicone. If perfect means zero sign of the cracks can now be seen, well, my work is far from that, quite "low budget." Happily, it proved to be structurally sound when we back-roaded on washboard in Montana last August.
Thanks much for the thumbs up.