I can see within eBay and Heritage that 'crayon' bag toning with some textile marks is the "it" thing for Morgans but I can't seem to put my finger on what the most desirable toning for copper is. Is a higher grade more preferred with copper cents?
I am not sure that there is a preferred for Lincolns. Aside from MPL's, colored Lincolns are much less common than Morgans and I think less common than all silver. The only 2 colorings I have seen with any frequency on Lincolns is purple and wood grain. Both can be all over the map for appeal and both seem to be less desirable usually. Crayon colored Lincolns are rarely slabbed and typically thought of as AT. I am not sure I am helping any, but that is my experiences.
Emerald green....very tough to find as it's the last real color before a coin starts to turn black. Most of the advanced copper collectors I know who actively collected Toned copper usually designated as BN on the holder can't get anough green
Depends on the series to me. Personally on wheaties I don't mind red(but prefer rb), but on IHC's I like the rb or bn high grade coins(not all of them). I like when you get the deep fiery red poking out around the edges and devices. Now the older copper(large cents) - I really don't like most of the high grade coins with red, but you start getting into high AU and some of those I like the red around the edges. I really like the brown coins the best - too me they just seem more natural. So toning is what catches your eye. Look at some of the penny lady's posts on IHC. Just my opinion on toning on copper.
Over the years I have picked up a 52-d, a 56-d and a 58-d all with incredible emerald green and magenta, just real eye candy and in NGC 65 RB holders. I also own an 05 Indian, NGC 64 BN that is 90% peacock blue (is that really a color?) on both sides. I bought the Indian raw and the 58-d in a double mint set, very happy with the grades and the color just blows me away. My 09 s vdb is chocolate on the obverse and wood grained reverse in an old anacs ef 45 holder, quite pretty also.