There was a very small amount of errata and a few queries and that's all listed on my site (in the sig). There's a thread for questions if you have any more.
Regarding ranges, I've never tried playing it with 15mm so I can't say. My first thought would be to play it with the ranges, table sizes and distances all as they are and see how that works. Most games condense ranges to fit a whole battle on a table and so it might just look more real (if a bit unfamiliar). If you want to condense the size of the battle you could always either half the distances and stay in inches, or play in cm instead. Heresy, of course, but I won't tell the Inquisition if you won't.
Playing with smaller measurements would also let you play on smaller tables. Given that it works fine in 28mm on a 4x4 foot table anyway that's likely to let you play on 3x3 or perhaps even 2x2 (if you went down to cm). Next step is a 6mm travel version.
As you say, you're off in uncharted waters.
Send up a flare if you get lost
