Tommy, 
I know you know this already, but I will reiterate: 
Sharp fixes everything. 

The backs on my incannel gouges are polished. Just at the business end for an
inch or so just because it made it easier for me to get the edge I wanted.
The challenge I faced when I first did them (a matched set of 12 vintage
Greenlee firmer gouges from MOfA) was not creating a tiny bevel on the back. If
it is rounded over at all it makes it hard to pare with them. So in that sense,
yes the back should be flat along its length to the edge. Now I'm not talking
about the whole 11" being flat, just at the last inch or two.

I then turned to the inside bevel with slipstones and a strop on a dowel rod. 

The next issue: if yours are the thicker firmer gouges like mine,  they are (for
me anyway) harder to pare with than a thin paring gouge. The thicker gouge wants
to lift the chips higher than the thin chisel and they break off sometimes
lifting wood ahead of them.

I suppose I could decrease the angle they are sharpened at and that would help,
but I kept mine fairly stout for the occasional chopping. I do have one thin
paring gouge which pares very nicely but it is too wide a sweep for most coping
work.

Brent

Sent from my iPhone
Brent Kinsey