Do you have to consider the 3" difference per level when calculating the distance from the deployment point?
What 3” distance per level? Just measure as normal.
Also there’s nothing to require you to place the JOP on the ground floor in a larger building though it’s common. You could place it on an upper floor if needed.
My friend has a sniper on a 20mm wide base that he placed at the top of a church tower. The base can only touch one wall at a time, but there is some argument that he can just arbitrarily shoot in any direction. I'm aware that it takes a CoC die to move him, but what makes it any different than having a team oriented out one side of a building, then having to use a movement to orient them out a different side? Seems a little o.p. having a unit that can't be shot, can see the whole map, ignores cover, inflicts double shock, and can shoot 360° in any direction. Makes maneuvering extremely tedious.
8.3.2
Vehicles firing H.E. at a building can fire at any point on the building they can see to inflict casualties on any men inside.
The sniper hasn't been spotted yet. I mean, logically, if a shot rings out from some random location, it can easily be assumed that it's a sniper in the only church tower in the town, and yeah, I'm going to start pounding it with my Pz.III from across the map. But is that how the rules work?
I would say that most such demolition was actually aimed at suspected FOO positions and took place at much longer ranges than on a CoC table. The rules don't include speculative targeting or reconnaissance by fire for a number of good reasons.
The 'snipers' in the rules aren't really professional trained snipers, who wouldn't be anywhere near the range of engagement on a CoC table, and probably nowhere near an ongoing battle. Such a sniper would, from the accounts I've seen, *never* pick anywhere as obvious as a church steeple to shoot from!
I think of 'snipers' in the game as sharpshooters, individuals who are good shots and have been given a roving brief by the platoon CO to harass the enemy.
Anyway, the sniper rules give them a fair amount of latitude, so I wouldn't get hung up on what model you are using or exactly where it's positioned. Just assume that he can see anything in a possible line of sight from where he is and is using whatever cover is available. A CoC dice is only needed to move to a different location, not just readjusting slightly.
If that sounds over-powered, bear in mind that most experienced players rarely use them, since they are largely ineffective - and if was umpiring a game in which a sniper used such an obvious site as a church steeple I'd give a bonus to spot them! ;^D