I’d like to repeat a request from earlier, shared by most of us in the xenharmonic/microtonal community, which is larger than one may think (and enormously so compared to my early days in this field several decades ago).
Once created, custom accidentals are currently easy to use for tempered tunings, where numbers of steps of a certain size define an octave. But it’s not feasible to produce music in pure tunings unless the pitch field is very restricted. For such tunings, “steps in the octave” is the wrong question to ask, because the answer is undefined, there being no enharmonically equivalent pitches. For pure tunings now, one must create a huge number of symbol combinations, even if the number of basic symbols is low. If I want multiple deviations by a harmonic 7th, currently I must have a font symbol for 1 such deviation, 2, 3, etc., both upwards and downwards, and then all the combinations of those with every other symbol.
The solutions to this problem are two, I believe: one hard, the other easy. The hard one is to redefine pitch delta by symbol as change in frequency. The easy one is simply to allow concatenation of individual symbols. The first is more accurate, although with a large enough number of steps in the octave, the second would work well. Concatenation has been used in other notation packages to good effect, although none of those is on the high level of Dorico.