CADding it out, on a 53cm frame, changes in seat tube angle will change saddle position about 10mm for every degree of seat tube angle change, at least in the 71°-75° range.

Depending on what one needs in saddle position to achieve good balance, this may or may not be an issue. I'm a long torso guy who needs the saddle all the way back on a setback post. Some bike and saddle combos don't have quite enough adjustment to suit me, but I get by. YMMV.