OK 2nd question of the night...
This is a general layout/geometry question.
I will try to explain my process step by step, then ask specifically my query.

I started my layout point at the BB...(This seems the most logical point to begin)
Then, from there I layed out the seat tube angle 73.5...
and followed thru with my top tube. I layed out my head tube at 73 and a length 160mm(that I just effing came up with for no knowledge based reason)
I connected the dots back to the BB to complete the front triangle.
I determined that I wanted about a 72mm BB drop and a CS length of 412mm...which a wheel fit into nicely.
All seemed well.
I took a fork similar to what I'm planning on using, to get the crown height layed out (with the 45mm offset)
After drawing out the fork, and the location for the front dropout...my heights came out different front to back.
After some adjusting (shrinking the HT length to 140) I made up a bit of difference.
Now leveling off of the two drop out points I have a real number of 68mm drop.
This is very close, and a usable number s far as I can see.

I think that I went at this backward...
My question is this:
In contruction the fork should be the 'known' factor, and the head length determined almost by default??
By subtracting the known fork dimension, from the TT position, the length fits itself, yes??
By pulling a number just out of my ass for a headtube without any relationship to the BB drop or the fork crown...
I had some errors to correct.
Black Sharpie is sooooo easy to fix with WD40.

What process, when starting from scratch, do you men use to obtain the HT.

You guys are show horses, I'm just a dumb old donkey....LOL

Luke