First, recall my front center non-rant.
Check it out: Richard Sachs doesn't measure (or know) the head tube angle or trail on any of his frames. Just designs entirely around front center.
Wow. I agree with ERichie that front center is super important - but I am amazed that you can produce a bike that rides well without taking into consideration, or even measuring HTA or trail.
To be fair, I think those things matter quite a bit more for mountain bikes (Sachs does only road and CX stuff). Still, an interesting perspective from someone who is the epitome of framebuilding success, with literally thousands of happy customers.