Doug Fattic 

Sure, the picture of the fancy lugged frame in the fixture has a 2º slope. It was designed for a short girl so all the tricks had to be used so the top tube could be kind of levelish with a quill stem. Her handlebars need to be as high as her saddle. She is a fast recreational rider but isn't racing through corners so a low bottom bracket height could be used (resulting in a longer head tube because the frame could be bigger). In addition a bit of height was added to the top of the head lug as well. She was one of my framebuilding class students that designed and cut out the lugs herself but preferred I did the brazing. She helped with the painting too choosing all the colors and doing the prep work while I did the spraying.

The next picture is how I design a frame placing the stem and seat in the same position that was established on a fitting bike on the fixture and then sliding the pieces that represent the frame tubes to match those components. In this case a 1º slope was chosen (look carefully at the mechanism that sets the top tube angle) because the lugs the student chose was 1º off from the design he needed.

It is a rare person that even notices a 1º slope even if looking for it. 2 degrees can be noticed if someone points it out but rarely is it obvious. 3 degrees and it is clear to see.