BF weapons - minimum range and arc of fire?

[Bluebell88A]

The following came up in my recent play of Airborne #1 Battery Position at Holdy:

Any thoughts on a minimum range for weapons using BF, under which it becomes a version of DF (point blank fire)?

How about restricting the arc of fire of an emplaced artillery piece to its forward 3 hexes, and it takes one GT to turn it to another facing? PL had an optional rule that there had to be a prime mover in the same hex to do this.

Tim