I test fired my PT145 with the Williams Fire Sights. See my previous post regarding ordering the correct type and installation issues. Before firing, I went ahead and widened the narrow rear notch, which was not very much due to how close the fiber optic knobs are to the edges. The sights are aluminum and easy to file, but you must be precise and even with appropriate square needle files. I finished with Aluminum Black. It did increase the too narrow light bars a small amount, still not as much as I like for precise target shooting.
The front sight is lower than the stock Heinie, so now my PT145 now shots exactly at point of aim, when before it shot low. The windage was spot on with the sights exactly centered, as it was with the stock Heinies.
The lighting at my indoor range is terrible for target shooting. There is glaring light from behind your shoulder, no overhead light, and very dim target lighting. That said, the fiber optic rods gathered what light there was and were very visible. The fiber optic dots change with ambient light and are brightest with overhead light. The dim target light made it hard to see the narrow light bars, but in a well lit room I can see them OK (after widening the rear notch).
The Fire Sights were not quite as target accurate as the well-designed Heinies, which have better light bars. I found that I shot better when I ignored the light bars and just concentrated on the front dot. For combat shooting, I imagine the Fire Sights would be easy to acquire, even if rough sighted, or looking at the bad guy over the top of the gun.