I've seen levers that are flat along the working edge and levers with a little indentation, like a miniature wrecking bar. Does anyone have an opinion about the pluses and minuses of each?
Yes, I would stay away from levers that don't have a completely flat side that goes against the dial. Anything that protrudes from the side of the levers that can touch the dial, can potentially do damage. For example these Horotec levers I would not recommend:
They have a very short curved area, and the spot where they increase in diameter at the red arrow can come in contact with the dial as you are removing hands, and possibly damage the dial (particularly an issue when removing hands from sunken sub-dials).
I use VOH levers:
You will see two things that I look for in levers:
1 - Flat on the side that touches the dial.
2 - A good arc in the lever that moves the hands upwards off the posts at a good rate for how much I move the levers, if you get my meaning. I don't want levers that I have to move a large distance in order to lift the hands off, because I don't want the handles to get close to the dial in this process.
3 - A wide surface area that touches the dial - this is important for spreading the loads as you don't want a small area of the dial taking all the pressure when removing hands. Of course different sizes for different hands are sometimes required, so I have a narrow set for removing sub-dial hands, and a wider set for everything else.
The VOH fit this bill exactly, and are by far the best I've used, and I've tried several brands, including the Horotec I showed above.
Of course adequate dial protection is a must, and you can see in the photo I use small pieces if soft plastic, stacked in layers (so you can change the thickness for the hand you are removing) and cut to fit around the posts, plus a plastic bag on top. When removing chronograph hands, that you note are on the posts very well, they come off with a lot of force. You need to contain the hand, because if the hand had lume in it, the whiplash effect from removing the hand can actually cause the lume to break out of the hand.
When removing a central chronograph hand (seconds recording hand) the plastic layers are built up so that the levers are just under the hand you are removing, so you are levering on a bunch of layers of plastic so no damage is done, and the handles of the levers are well way from the dial.
Removing hands from a watch is one of those things that requires complete attention, because if you damage the face of the watch your customer is going to see the result of your inattention every time they look at their watch.
Hope this helps.
Cheers, Al