What is the difference between "Rear Echalon" and "Support" in Field Positions.

[Panpiper (OP)]

What is the difference between "Rear Echalon" and "Support" in Field Positions, and what are the use cases for each?

Also, it there any way to set field positions for various units, without having to do most of them one by one? This can be especially tedious if fielding multiple, deep formations.

[brondi00]

http://aurora2.pentarch.org/index.php?topic=10666.0

This is a table of contents for all the mechanics changes in c#.  It includes a lot of info on ground combat since it was a major change.  Front attack, front defense, support, and rear echelon are all discussed.

When you change the field position of a unit you can tell it to change all the units below it too.

So I will go to the brigade hq of,say, armor, and select front attack and check the box to change for all subordinate formations and all the armor becomes front attack at once. 

That makes it a little quicker. 

[nuclearslurpee]

What is the difference between "Rear Echalon" and "Support" in Field Positions, and what are the use cases for each?

Rear Echelon is even less vulnerable than the Support position to being attacked in general (5% vs 25% weighting). Otherwise, it's mostly artillery mechanics: heavy and long-range bombardment elements can fire from the rear echelon, while medium bombardment elements can only fire from the support echelon. Similarly, medium bombardment can only target enemy formation in the front line ans Support positions, while heavy/LR bombardment can target the enemy Rear Echelon.

Also, it there any way to set field positions for various units, without having to do most of them one by one? This can be especially tedious if fielding multiple, deep formations.

Sadly not, the only bit of automation we have here is the ability to set position for a formation and its sub-formation.