Thank goodness I'm not crazy after all. The reason I haven't been able to repair the inner fender is that...ta da! it's not repairable!
after much reading I began to realize it is made out of something really tough, like polypropylene, which apparently does not lend itself to repair, chemical or heat type welding.
I got hold of a pro, Owen Ford at
http://expertplasticwelding.com and he confirmed it, polypropylene. unfixable. He described my part to me as though he had one in his hand. Hard, black, glossy finish, etc. Best I can determine Honda and others use it for inner fenders as it is so close to the battery acid. And road debris. Virtually indestructible, except when its destructed. Then its unfixable.
He actually said he could "weld" it, but it wouldn't hold, it would be ugly, and I woldn't like the result. Nice he was honest about it.
He did say that on some dirt bikes, he would drill a series of small holes on either side of the wound and stitch it up with stainless safety wire.
So now i get to decide to leave it, stitch it, or look for a new one. There is an OEM on eBay for $75.
So the MEK, even the PVC and ABS glue type mends would likely work on anything except an inner fender. Maybe even the airplane glue.
So those of you with good ones, take care of them. Soak them in your favorite conditioner to keep them soft and pliable. Parts solvent (diesel) is doing wonders for mine. Though it still has a crack.