Gas in W-space
Ladar sites (along with Grav sites) are the most prevalent in W-space so they are never too hard to find. Most people leave them alone cos it doesn't make anything go boom. In Class 1+2 W-Space Systems you can find Perimeter sites, in Class 3+4 You can find Frontier AND Perimeter sites and in Class 5+6 you can find Core and Frontier and Perimeter sites.
As with Grav sites, the sleepers in Ladar sites do not appear on warp in (with one exception) but rather appear roughly 20 mins after the site has been activated. If you are out in your scanning ship you can just select "warp to" so you get the pop-up box and then cancel warp. Wait 20 minutes, and you can just go back and grab your site clearing ship first rather than mess around with changing ships and back and forth....
Types of gas
Name Volume Found in
C50 1m3 Perimeter
C60 1m3 Perimeter
C70 1m3 Perimeter
C72 2m3 Perimeter
C84 2m3 Perimeter
C28 2m3 Frontier
C32 5m3 Frontier
C320 5m3 Core
C540 10m3 Core
Site Composition and Defences
Name Gas1 (m3) Gas2 (m3) Sleepers
Barren Perimeter 3000 C50 (3000m3) 1500 C60 (1500m3) 5 Frigates
Token Perimeter 3000 C60 (3000m3) 1500 C70 (1500m3) 1 Cruiser, 2 Frigates
Minor Perimeter 3000 C70 (3000m3) 1500 C72 (3000m3) 2 Cruiser
Ordinary Perimeter 3000 C72 (6000m3) 1500 C84 (3000m3) 5 Sentries (present immediatley upon site activation)
Sizeable Perimeter 3000 C84 (6000m3) 1500 C50 (1500m3) 6 Frigates
Bountiful Frontier 5000 C28 (10K m3) 1000 C32 (5000m3) 4 Cruisers, 6 Frigates
Vast Frontier 5000 C32 (25K m3) 1000 C28 (2000m3) 4 Cruisers
Vital Core 500 C320 (2500m3) 6000 C540(60K m3) 4 Advanced Battleships, 4 Frigates
Instrumental Core 500 C540 (5000m3) 6000 C320(30K m3) 4 Advanced Battleships (The only Ladar site to have Warp Scramblers)
A note on sleeper enemies....
As mentioned above you can find sites below the class of wormhole you are in (i.e. a Barren Perimeter in a C4) but the sleepers you face will have the same stats as if you were in the native class of W-space. So a Barren Perimeter site, even if it is in a C6 Wormhole system can be soloed by a cruiser although why you are taking a cruiser into a C6 is beyond me
The Value of Gas
Gas does not have to be refined in order to use it, as Ore and Ice products do. It can be used as is in T3 production by turning it into a polymer using a Polymer Reactor Array. The difference in value between gasses can be extreme, due to the scarcity of the gas and the value of the end products. At time of writing C84 is worth around 180 isk/m3 while C320 is worth around 17,000 isk/m3! However getting to C320 can be very difficult so a tip for beginners is to harvest C50 which at time of writing is the second most valuable gas at around 7000 isk/m3. The sleepers can be cleared very easily and the site can be cleared very quickly due to the small size of the gas.
A note on the more valuable gasses...
When you start getting up to the C320/540 stage you will need several people working together to clear the site due to its size. You will probably need haulers and also someone acting as a dedicated scout. Remember, there is nothing like watching someone clear a site then ganking them and taking all the gas it took them hours to harvest in a matter of minutes. Don't let it happen to you.
Ships and Fitting
A battlecruiser works well for this due to its cargo size and Grid/CPU output. If you have someone with good leadership skills then a Mining Foreman Link - Laser Optimization gang link will reduce your harvester's cycle time. Other links do not affect gas mining.
For the rest of your fit, a Proto cloak, probe launcher and cargohold expanders are the order of the day. Oh yeah a Scanner in a mid slot is useful too so you can see how much gas is remaining (you only need a T1 scanner as you have to be 1500m from the cloud to harvest so you don't need increased range). A bit of tank is handy and cargo expanders in the lows. THERE IS NO EXCUSE NOT TO FIT 2 WARP CORE STABS! I cannot emphasise that enough. If your constant spamming of D-scan is not enough to see someone (and in a lot of cases it won't be) then if one person warps in they will need a faction scram to catch you. If they can afford that then chances are they have a much better ship and more skills than you so you are dead anyway. Otherwise a big gang will drop on you with multiple scrams in which case you are dead anyway. Two stabs are just about right for this. You may also want to fit some sort of ECM in the mids but that is up to you.
Gas harvesting is very dull as you don't even get the "click-drag" every 3 minutes that you get with regular mining. You also don't get the nice visuals you get with regular mining. You just sit there and wait for your hold to fill up before jetcanning the gas, which can take as much as 15 minutes. That said, it is VERY profitable. You can get close to 200M isk/hr from harvesting C320 at time of writing, which far negates any boredom you might get. Use it in T3 production and you can make it even more profitable. Even turning it into polymers can make it more valuable. (And a lot less bulky).