YEP! This is the way to do it right. A few year ago, I had some major a$$hole "certified marrine mechanic" do $560 damage to the transom of my mint 311 pulling off a trim tab with wedges, a sledge hammer, and crow bars. He was about to do the same thing to the other side when I just happened to walk in before he did further damage.

I have never been more pissed and seriously considered applying the crow bar tightly to his head repeatedly!

Definitely if the tabs are older and the hinge pin is siezed, you won't have much luck getting it out. There is just too much surface area and it is a pretty soft stainless steel. I've tried that, and gave up long before causing a lot of damage. I was actually doing the opposite of the thread, trying to paint the tabs. I ended up just masking off the transom of the boat, sanding/grinding/sandblasting the tab down, repriming and painting on the boat.