I'm sorry. My ignorance isn't on purpose, I wasn't sure what 68 down means in the terms used by others. Might be elevation, sorry.
I holed it at about 163 fbs with wind at my back, maybe 11mph? can't recall. Anyway, is it right in that area. But I also used a wgt 1-0 ball so makes a diff when factoring in the big spin balls.
Good Luck!