I cut it with a hacksaw then faced it in a mill to make a clean cut. I then used a 9mm comp alignment reamer to double check that I didnt have any burrs in the path of the barrel.
I haven’t cut a tangfo comp but i did cut a 4 port egw comp down to 2 ports for my steel gun. It’s holding up fine (~12000 rds of 100pf). The only downside is that the front of the comp is angled
Why have it in a holster and not in a bag? I have seen so many issues with holstered pistols at steel matches, guns become too dusty or falling out. Not worth it, especially when you can bring your bag to the line with you.
I use a big black thick sharpie. Works great for the day but I have to do it every time I want to shoot, I became annoyed and just purchased a new sight.