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The maximum power based on 0.5mm exit pupil is 710x for the 14" and 610x for the 12".
The theoretical maximum resolving power of a 14" must be better than a 12". Dawes limit = 4.56/D in inches. eg. 4.56/14=0.32, 4.56/12=0.38.
Rayleigh criterion is the other indicator of resolving power and leads to a slightly higher result but nonetheless cannot be equal for both 12" and 14".
Faintest visual stellar magnitude of 21 for the 14" is grossly in error. The value should be more like 15.3, slightly more than the 12". Note magnitude is a log scale and a small rise does in fact lead to many more fainter stars. Note too a better indicator is light gathering capacity which can be compared by the squares of the primary mirror areas. The 14" has 1.36x the light gathering capacity of the 12"
Note the f4.7 of the 14" would be far more demanding of your eyepieces unless they were highly corrected and in any case will show more coma (a function of the primary mirror). A Paracorr will correct for coma but at 1.15x to the focal length/ratio so f4.7 becomes f5.4, f.l.= 1700x1.15=1955mm. You may find that coma is not objectionable on an f5 system provided you still use highly corrected eyepieces corrected for eyepiece astigmatism.
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