I went out and straight edged my Tommasini Diamante frame. I couldn't detect any issues on downtube.

Top tube looks to have a little bow. Measuring from the top, I couldn't see a gap. However, measuring along the bottom, I could. Tough to get pictures, but this is the worst.

The max point of the gap I can get a .005" feeler gauge through with some friction. There is no visible buckling. At one point on the downtube I can feel a very slight wave.

Opinions?