[Mobhack]

Spotting is based on experience, not unit class - though vehicles spot infantry less well than other infantry. Remaining stationary, or only moving a hex or so per turn makes spotting more likely (and the faster you go, the more likely to be spotted).

Scouts have no extra spotting ability, thier size 0 may help them get a little closer and so spot an enemy before he sees them - provided they move slowly.

"fighting hard targets" - I presume you mean assaulting AFV?. In that case having an anti-tank weapon is a major factor, as is experience and morale. If the AFV is open-topped, it is very vulnerable. Also, the less hexes you move towards the assaulted AFV the better your chance.

Firing HMG sections (2 or more H/MMG in a unit) - I never turn off the barrels. Sometimes it is good to spread fire over several units, especially when the enemy is bunched up - HMG have a 1 hex blast radius and so firing at several units in a clump can help to "spread the joy" amongst the clump, though shots that miss can do the same effect anyway, and the multiple barrels in the one unit make sections much better at the job than "singleton" MGs. Also good to shoot up oncoming enemy tanks with as they may have tank riders which will take casualties from MMG fires on the tanks. And a wonderful toy to deal with any enemy that decides to come at you with truck-bone infantry!.

Main thing to remember with H/MMG is to keep beyond enemy infantry LMG range - they will start to take return fire at 600m, so a firing range of 700+. The AI will treat them as priority artillery targets once spotted, so have a half-track nearby to scoot off on if you can.