jjames2b- I just ran your givens through Bikecad. As you see your front center is about 30-35mm less then what 170 arms would want for no overlap. This is a lot of overlap in most books. The TT and DT do have some overlap, the HT C-C is only 12mm, a HT C-C of about 30mm (with traditional tube diameters) is about the minimum and still have the lug points not completely gone. Your straddle height is just over 30", real tall for my 29" inseam. I got about 54.7* for the DT/ST angle, worse then your 56* as far as needing to change a shell goes.

I did make some assumptions to fully calculate the geometry. The tires are 674 in diameter. The chain stay is 430mm , but these don't come into play where we're talking about. Tubing diameters are larger then classic ones.

I'll redo the design with some changes and post that in a few minutes. Andy.