I just started playing with Gravity wells just the other day and I came across a Voth Ship, in a group that was by one of the towers at the Dyson Sphere battlegrounds, anyway I just trying to pick off one or two from the group, put the odds in my favor of taking over the tower, Those Dreadnoughts are not something you want to screw around with other ships there protecting it, but in this group are corvettes, cruisers and battleships.
I believe it was the battleship, and everytime I would try and kite a cruiser or corvette away this Battleship would do a little hop-stech over and get just in range and drop a gravity well, wow that sucker had some mean bite to it. Usually I'm the one dropping the gravity wells, the one time there just before the server was about to go down for maintenance I got snagged for the full hit, down to 33% of my hull, very lucky I did not have any pursuers or else they definitely would have had me at the disadvantage, who ever did the layout did a good job of kitting as the group had a certain distance and secondary line was for battleship. If you didn't commit than they would go back to the group and do a fleet heal, and repairs.
As much as I was kitting them there were kitting me. there is a sucker line there The moment you commit over that line and start to engage, that's when the whole group moves and you have that dreadnaught jump right beside you and at 33% health your going down, cause your going to need to spam heals to just get that back, now they do tell you to bring a friend with you.
The thing you need for a gravity well is lots of power "Auxurally" this also affects it's damage ratio to power your giving it. For myself I'm not not willing to make that my speciality, different say in a group your speciality for that is required, so you can hop in a custom gravity well build ship and go with a group, you be lacking in other areas and will need that reinforcement from the group. So basically your a wrangler piling them all in barrel and the group shoots at them :) and hopeful it causes dominos explosions.