Good point NWH, I think possibly it may be a case off over thinking things, sat there in a south facing room expecting your windows to be perfect, then start imagining what the custys are saying in their south facing rooms 🤔 . I doubt custys get their noses right upto their windows examining every inch after we've all been . I suppose when you try your hardest to do a perfect job, you will never be satisfied as you could've done something better.