I have been working for the past few months in Illustrator on a display family with lots of alternate glyphs and ligatures and would like to begin the process of creating a fully functioning OT font in FontLab 5.0.2. (on Mac X)
I have never used FontLab before and this business of a UPM value of 1000 throws me already off. The number 1000 seems such a unyielding beast regarding it's compatibility with other numbers. It cannot be cleanly divided by 3 to start with. Could I use 1080, for instance? (With the exception of 7, it is divisible by any number between 1 and 10 and by 12, 15, 18, etc.)
Or is s there a way to get around those rounding errors by choosing a number lower than 1000? In my case, the number 864 would allow all points in all weights to fall precisely on the grid. (the design has a few decorative elements, like seamless patterns for each weight, for instance, which I would like to remain seamless)
Any input on this would be greatly appreciated!