Chain tensioners are wonderful devices, with the bearing races almost all bikes use press fit races, just pound the things out I use chisel with flat edge, and like said before get a block and wail it back in. They are steel and so long as your using wood you are not going to hurt anything, you could also make you own press that's what I ended up doing. I had a problem with missing the wood and dropping the hammer on the frame, i just got some 3/8" all thread some fender washers and nuts and two pieces of flat steel works like a charms.
I would say the rear drop outs look very good I wouldn't be too concerned with the darkness of primer the only time that really affects color is if you are using a light color or translucent type paints. Gray tones and blacks unless they are a metallic paint don't change much at all with different color bases.