Developer of Pegasus here:

I hear what you say. The idea is not to necessary replace IB, but to provide an alternative.

Next step is to include layout managers (similar to Android/Swing) which will automatically lay out views based on some pre-defined templates (e.g. i*j grid, horizontal, vertical, etc.) which will remove the need for randomly tweaking numbers as you say ;-)

(Said so, this is how a lot of developers tend to work already...)