I wouldn't be too worried about frame weight on a SS/FG, nor would I be too concerned about the headtube diameter.

As a car replacement, I would not be interested in a track bike unless your idea of groceries is a candy bar and a pint of Kentucky Tavern. Aggressive geometry and 30-35c tires don't belong in the same sentence.

Figure out what you want the bike to be used for, then find the bikes that will fit the bill.

btw, where did you go to school?