Top tube downslope angle

The geometry I worked out for a possible XACD roadie, had a 8 degree slope. This was pretty much as high as I could go without breaking the all important seattube cluster above rear tyre rule.

ETT . . . . 535mm
HT . . . . 121mm
ST (C-C) . . . 460mm
ST (C-T) . . . 609mm
CS . . . . 403mm
BB Drop . . . 74mm
HTA . . . . 73,0º
STA . . . . 74,0º
TT Slope . . . 8,0 º
Saddle height . . . 695mm*

i totally agree with this. I was mainly speaking my my persepctive which is at least a 56cm frame. But yes i agree completely with this aesthetic point.