Yeah I came here to say this. The BSP rules found in the Battlemech Manual are great in limited quantity to add some support.
The problem with the full artillery rules is how overpowered it is. The side with artillery has a massive advantage against a side without artillery. So then both sides want more and more artillery. To add insult to injury, artillery units are irresponsibly cheap, like many are less then 200 BV. Resolving artillery adds multiple new phases to the game, the targeting phase and artillery attack phase, so it also slows down the game. When I play with artillery for campaign stuff, its usually a 'enemy base' boss battle type thing to force the players to move each turn, and I put the targeting hexes down (not hidden) to make the fight more like a MMO raid 'danger circle' so the players can move to play around it.
Instead of full artillery for non-campaign matched play, I really like 5 points of BSP for a 4v4ish game with objectives. It gives enough for a single sniper or thumper blast, or some light/heavy bombs, as a 1 time use. It helps deal with battle armor and light units like dashers which otherwise can hold/steal objectives for very little battlevalue--the threat of predesignated artillery on an objective means the enemy cant just put a 400 BV unit on an objective and call it a day, but the fact you only get 1 shot means there is some interaction.
As a side note, playing with objectives and not just 'kill each other' also really helps reign in 'turret tech' better then adding in artillery. If there is something in the middle of the board that needs to be held, and the snipers are in the back in their heavy woods, well they arnt gonna win the objective from back there.
Funny, I never found one gun to be of any use. Artillery has this weird 'curve'. One tube, you might as well leave it in the dropship with the spare parts, because you're running higher risk of friendly fire, than harming the enemy (Guided rounds cancel this, I'm talkin' dumbfire shots only)
The minimum USEFUL kitting out for artillery on two mapsheet map, is four tubes. with four tubes you can establish something of a useful pattern for terrain denial or camper harassament. This scales up to 2x3 maps before you start needing more, or bigger, guns.
the MAJOR problem, is that artillery rules themselves, are very clunky, with flight times and the rampant inaccuracy of dumbfire artillery, coupled with the sandwich-plate blast radii (out to dinner plate on the bigger stuff), though they at least got rid of the open-ended scatter they tried to incorporate in TacOps.
The blast radii and damages? are very OP, especially with the stats given in Tac Ops, where 200 KG of arrow IV or Long Tom does more damage to a larger area than a full ton of air-dropped bombs. (this is because the air-dropped bombs were balanced against BMR(r) artillery, while Tac Ops went hawg wild porting over Munchtek's or Unbound's enhanced blast radii.)
To the OP:
if your group's having issues, go with the light guns. Thumpers, the blast radius isn't insane, they're still effective enough, the scatter hazard's not too bad {You' won't be greasing your own units on a bad role quite as hard) and the assault campers can look at the damage rates, and either grit their teeth or go watch Football.
if you do, work them in in pairs. as I said, single tubes you might as well leave on the dropship if it's not homing rounds with a tagger, because artillery is one thing above all else:
dreadfully inaccurate and prone to scatter.when coupled with the bigger blast radius, this means you might completely annihilate the chicken coop behind the enemy, or bounce a shell right on your own guys, but whatever it is, if it wasn't pre-registered before play began, it's not going to be particularly useful or valuable if you only have one tube.
IOW instead of a force multiplier, a single tube firing non-guided artillery munitions is a force divisor that costs you BV and maybe c-bills, and can actually lose you the engagement on a bad roll at the worst time.
Some things to keep in mind?
1. It gets less useful the closer you are to the other guys. This has to do with scattering back. Keep in mind the maximum range of the scatter in the rules you're using, when planning to use it.
2. have a plan of when NOT to fire. For example, when your BA or INfantry is in close contact with the enemy, or when the other side has closed to AC/20 or Melee range.
3. When using a useful amount of artillery (3 to 4 guns), plan your drop ahead of time, decide what terrain you're trying to deny or what avenues you're trying to keep open, and place your shot accordingly (at least, in theory-the odds are against your shots actually landing where you want them to!) I call this 'pattern' because It's spaced to deny an AREA-to make it hazardous for the other side to come through that area-and if they do, to give them pre-existing damage before they reach MY guys.
4. if you're using pre-registration? look at the map, and know where the best 'camping spots' are (woods hexes on elevations, lee side of a hill with partial cover, etc.) THOSE are where you want your artillery pre-registered before play.
5. go over the spotting rules and make sure you understand spotting, and scatter, maybe pre-game it to make sure you're not skipping over something that is going to demand opening books and arguments.