Scott there's no way I would have lapped both sides even if I had the patience...
It took me close to 3 hours to get the middle 7 inches or so flat and the etch pattern persists at the short edges at the ends of the long sides. I was satisfied that would be enough.
It really is a very different hone on the lapped side.
It also completely broke in my DMT 325 which feels great now. No bumpiness at all but still has texture - I was worried for a while that I'd screwed it up!