2) should give you a sweeter beer since you'll have more residual fermentable sugars which are sweeter than the unfermentable sugars you get from 1)
This is partly where my question came from, i.e., the nature of the sugars that remain after fermentation.
I have the book "Brewing Science and Practice," by Briggs, Boulton, Brooks, and Stevens. In chapter 4, "The Science of Mashing," on page 135 there is a figure (fig. 4.20) that shows the various sugars created at various mashing temperatures. (glucose, maltose, maltotriose, sucrose, maltotetraose).
I know that a part of yeast attenuation comes from what sugars they are able to ferment...and I saw in the same book where sugars have varying degrees of relative sweetness, as well as differing taste detection thresholds.
And so I was totally thrown off by the appearance that lower mash temps made more of the sugars that taste sweeter, and high mash temps just the opposite. And then throw in the variable sugar fermentation character of yeasts, and you've got one confused homebrewer!
So I thought I would throw it out here, and see if anyone had some sound experience with mixing up mash temps and yeast attenuations.
And maybe some practical advice as to how one might exploit combinations of mash temps and extreme yeast attenuations.
Thank you all for responding.
Anything else you can add?