Depending on the TASK , this ratio can be changed --a lot -
That is the reality of the arrangement -
Example
the ratios for a stable glider is different from that of a extreme aerobat setup.
Also - if the aerobat is required to do "departure " maneuvers - that is tumble - a smaller forward mounted stab works better .
For the record - this is the arrangement used on the CAP type 232 .
The best setup is defined by the task -However
The ratios noted are fine for stable craft.
I guess you are referring to balance point (CG) location, which the above calculator doesn't calculate, since you have to enter your own value as % of MAC.
The calculator is supposed to calculate the Neutral Point (NP) location, which seems to be too far aft, since the resulting Static Margin for a typical CG location is about 40%, which is far from the typical 5% to 15% as suggested in Geistware's website.