zymphad

I built up a new bike from Winspace SLC 2.0. I went a size smaller this time around and rather than focusing on the height and top tube as I had sized my prior bikes, I instead looked at the reach, stack and head tube.
My prior bike I had cut the steerer tube and was more aggressive, this time around I kept some extra space.
Now I am using a straight seat-tube without offset.
And I also upgraded the pedals to the +4mm Ultegra Pedals

With all this combined, it's made for a lot more fun to ride bike.

Iride01 

I can't fathom what head tube length has to do with a persons fit to a bike. But it's okay if we disagree. Similar to seat tube length, it can be different for bikes of different models that will still give you the same fit on that bike.

Reach and stack do work well to get you in the ballpark for picking a bike that might give you the fit and position you wish to have on the bike.

When you said straight seat tube without offset, did you mean a zero offset seat post? I too like the more forward position a zero offset post gives the saddle since when I'm on the bike, it's seldom a leisurely pace I'm doing.