What would you use?

For hardiness, trifoliate (regular) or Flying dragon "lime?" -- the latter supposedly much better tasting

Trifoliate or C. taiwanica? -- the latter less bad tasting

As importantly. what good tasting citrus would you use as the cross? It should best be monoembryonic. What would be a good choice? What is monoembryonic? Clementines? Others?

Also, there is supposedly a less offensive trifoliate selection growing at the edge of the Augusta National Golf Couse, site of the pre-Civil War Fruitlands Nursery and possibly related to that (I'm told). I recently collected fruit and thus seed from there but am not experienced with the "regular" trifoliate, so I don't know how much difference there is. It certainly wasn't "good."

In any case, it seems like we now have a chance to do better than Swingle did a hundred years ago. On the other board (GardenWeb) there is a person reporting important new experiments along these lines, but I cannot tell whether it is with the same old material. Still, more trial (higher number of seedlings) can only raise chances for good results. But you wonder what a better tasting source of cold hardiness could do. And maybe with a fairly cold hardy sweet "partner," to allow a later F2 selection to be only one-quarter "bad" but still quite cold hardy.