Exploring the two octave model is a good start with a separate hand approach to clarify fingering.
I prefer making an adjustment for the opening F#, G#, A in the Right Hand (2, 3, 1) instead of 3, 4, 1
When considering a fast tempo, 2, 3, 1 is less awkward than passing a thumb under 4. The same adjustment works well when concluding the scale on the descent. (RH 1, 3, 2)
In the Left hand, I make an adjustment at the peak (F#) using 3–Which matches up with the same finger 3 in the Right hand at that juncture.
When playing hands SLOWLY together:
In the body of the scale there are cohesive MIRROR points between the hands at the F# G# juncture (Reminder: this reciprocal relationship occurs in the second octave since we made the opening finger adjustment in the RH, 2, 3, 1). In the subsequent octaves, while the LH uses 4, 3, (F#, G#) the Right Hand enlists 3, 4. (F#, G#) It therefore makes sense to BLOCK out the MIRROR points in the scale going up and down (by octave)–Note that the upper most F# that terminates the scale uses finger no. 3 in both hands. (another symmetry)
Finger no. 3 of both hands also meet on C# through the body of the scale, so marking these points out should be helpful in a practice regimen.
Identifying ORGANIZERS belongs, in part, to the COGNITIVE dimension of scale playing, though having cerebral knowledge is surely not enough. The Cognitive must fuse with the Kinesthetic and AFFECTIVE aspects of playing to foster beautiful musical expression.
F# Minor Arpeggio
It’s best to practice a slow rendering, separate hands, for fingering clarification then to notice symmetries between the hands.
Thumbs will meet on As as the perfect 4th, C# to F# will have MIRROR fingers or reciprocals. (RH 2, 4) and LH (4, 2) on the ascent and in reverse F# to C# when descending. (RH 4, 2); LH (2, 4)
Blocking out these perfect 4ths with thumbs meeting in between on A, is a thoughtful approach to practicing them. (The attached video will illustrate physical motions in greater detail)
Finally, Arpeggios are rolling figures that enlist supple wrist motions. Even rendered in Staccato they have a well-shaped contouring that suggests a SNIPPED LEGATO approach to preserve their curvy shape.
Above all let the playing of scales and arpeggios give full reign to the musical imagination so they’re not churned out like pedantic exercises.