Two quick questions
 

1. Meeting Engagement, no artillery plotting is allowed? Screen shows message "Plotting Disabled due to Mission Type." Does that mean off-board artillery is worthless in this battle?

2. Building heights. The screen shows two numbers. Is one the ground level of the building and the other the top? Related question, are infantry assumed to be at top, bottom or what for spotting purposes (spotting out and being spotted)?

Re: Two quick questions
 

1.) Artillery is still useful in a meeting engagement, you just cannot plot it during deployment (and maybe not on the first turn of the game). But after a couple of rounds you can use it normally. Same if you are defender on delay or defense scenario.

Re: Two quick questions
 

Point 1 - please see the release notes for version 7 (6 for WW2), its in your game guide. (Game Guide -> Release history, scroll down to the appropriate release number).

Refer to the paragraph beginning "Artillery can no longer..".

So - of course you can plot arty, once the game lets you based on mission type. You cannot plot pre-game bombardments or artillery programmes though. Scenario designers, and the AI, can however. Simply wait a game turn or so till your artillery is released to you (same as minelet batteries were already).

You can plot your artillery hot-spots pre-game as before of course. This will be vital if you bought glider or paratroop planes! - since you cannot pre-game plot these and they have deliberately high delays inbuilt, as with level bombers.

Thus - pre-game bombardments are now only options for attackers/assaulters as they should be. Defenders and meeters cant casually bombard the packed deployment area of the opponent before the game starts - unless the attacker, onto the prepared and waiting defender.

Part 2) One height is ground, other is obstacle (cover) height. And as far as I can recall from the spaghetti, it is the ground height that spotting is done from (or troops in tree hexes could see some very long distances!). The 2 heights added together are used for LOS blocking calculations though.

If you are really interest then make yourself up a test scenario with a building and then check arcs, then edit the scenario and remove the building from the test hex and see if it makes any difference whatsoever to what the reference unit you placed in that hex could see.

cheers
Andy