)so there are design elements and constriants when doing a pert calender chrono, versus a flyback chrono.
also, when collectors speak about the 5270 being "bottom heavy"...its relative to the 5970. the 5970 is 1mm smaller, but its not really the case size ....its the dial design. the 5970 has the moonphase and date counter at 6 oclock "protuding" onto the outer rail, whilst 5270 has the whole counter within. the 5970 also has higher sub counters...the upper ends of the counters almost level with the Patek Phillpe words, whilst the 5270 has a more "recessed" sub dials.
best, Horo