OK guys, caveat here - these are exterior sashes and you can't see the munton bars that well from the sidewalk. At least that's my theory. Also, I'm not doing a 100% replacement on the glazing compound, only where it needs it. So a pic would only show you that I've painted a perfect line over bumpy old glazing compound and the previous painter's paint.
I will declare that I have zero cleanup of paint on the glass panes. Not trying to dodge the challenge, but my point is *my* paint job is great, but the foundation I am painting on isn't the best.
I use a 1 1/2" tapered trim brush, and hold it like a pencil. Fairly wet and bend the bristles fairly well. Don't paint with the "feathers" or tips of the bristles. I put the brush against the trim (bent bristles), then let the brush "fall" with gravity, sliding on the paint film. My hand is only guiding the brush as it falls, I'm not pulling or pushing it. This technique is for the vertical bars. Horizontal ones you need to pull the brush, but keep the bristles bent.
I think the true test, which is highly visible, is the wall-ceiling juncture. I don't think a close up photo is fair because you don't look at the ceiling with your nose bumping into it. Your dinner guests will not climb up on their chairs and inspect the cut-in job on the ceiling. They will simply admire your perfect (in appearance) work from the comfort of the table, sipping their coffee.
No flaws will be evident from normal viewing distances. I had a team of pros paint the inside of my house when we moved in, and even they aren't perfect.