2 251s will kill a vbase's VHs much faster than any other GV can, and capture it to boot. 12 rockets per VH == 2 loads of rockets. If you do it just right, you can deack the field yourself, which means one possible plan is to have 1 SDK carries rockets+supplies and another rockets + troops, so one of them kills one auto ack and the man ack + the two main VHs, while the other kills the map room auto ack and its VH, and drops troops..
If you have macro abilities, you can do it even faster, salvo 6 rockets, salvo 1 supply (not needed unless you're 800y from the enemy spawn), reload yourself (put the mouse in the top left corner ahead of time..), salvo 6 more rockets. That's barely as much time as a tank takes to shoot 2 to 6 rounds, depending on your range to the target - meaning that from close-in you'll have to be rolling towards the VHs and are spending more time accelerating fast enough to reduce the rocket range.
Still a pretty expedient method.. The real difficulty is getting the ack yourself with just 1 light MG. With this plan, you have the option to have the 2 SDKs rolling together rather than separately (e.g. 100y apart rather than one at opposite ends of the vbase - 1 map room side, 1 main pad side) and share the auto ack fire, which is risky but not guaranteed to kill you. Usualy the front tires get hit a relatively long while before anything else breaks, and the supply SDK can afford to drop 1 box of supplies for all the VHs to be disabled.. Both front wheels damaged means you'll still be able to move, but won't be able to steer.
Alternatively, you can leave the map room VH up (buys you a few seconds and degrees of angle of cover from spawning GVs' fire) and spare 2 supplies total.. although that's depending on your exact tactics, since you might as well not be killing any VHs and sneaking the map room, which the 251 isn't the best tool for.
I personaly can't estimate the distance to targets with enough accuracy to be wasting a negligible amount of rockets.. You can sort of range yourself with the front MG (it goes out to 1.5K standing still).. If you can get a friend to bring a tank to range VHs for you, you can really put the artillery to use as it probably was in WWII.. Drop the supplies before firing, and you can have the target VH down in two pulls of the 2nd-fire trigger and one mouse click. Just one pull of the trigger if you've got two friends, one ranging the VH in a tank, and a second 251.
An M8 can probably scout ahead to find a good spot with the right range ahead of time while the 251 is on its way.. There's no need for a heavier tank, since the 251(s) will drop the hangars in a hurry, provided it gets there.
Note that ranging with the tank sights requires some correction if there's a difference in elevation between you and the target..
So the 251 is pretty useful against large static targets. It also works handily against shore batteries. So far I've not been able to do any damage to armored GVs.
