Homebrew PCBs

I use Ultiboard, so have the option of generating output in HP 
Graphics Language or Gerber.  Looking at the file of the same project 
produced in the two languages, it seems to me that it would be 
fastest to use a translation of Gerber to HP G/L -- convert 
the "tools" that Gerber flashes for different pad sizes and trace 
widths to different pen sizes.

With HP G/L and Ultiboard, a circle is drawn with the "Arc Absolute" 
command, using a chord angle of 1 degree. This is very slow. I 
use "Search and Replace" to change the chord angle to 15 or 30 
degrees which speeds it up dramatically.  I guess you could 
use "Search and Replace" to draw a circle using CI, but this assumes 
that the current pen position is the center of the circle (which it 
is not) and you need to recalculate the coordinates with a little 
trig to determine the true center of a circle.