Ideal lie angle mark = center to slightly heel bias with a very thin looking mark and close to the leading edge
As long as the ballflight was desireable.
Not in my opinion...you shouldn't be adjusting the lie angle to compensate for some ballflight problem you are having; that is what the OEM do's and why most iron manufacturers "standard lie" has gone 3-5* upright than historical to compensate for all the slicers out there too.
Lie angle is all about the ball flight:
eg. -draw toe closing front edge mark - fade heel open mark mid sole
However there are so many factors that could change the mark that it would be impossible to provide a precise answer on a computer forum.
Non golf instructor club fitters cannot cut the mustard in fitting as they cannot link the swing/ ball flight to the club specs.
The most common problem I see is the misreads taken off fat shots hitting a lie board behind the ball, or a closing mark read as a flat mark.
We all know how deplorable the level of golf instruction is in the world don't we; well the level of so called clubfitting is as bad as the level of instruction.
So, what are some basics that the average forum member needs to know keep their crappy local club fitter in line?