Hello and Good Day!  I am a relatively new student (7 months) struggling with getting my fingers on the appropriate frets when playing individual notes.  Up until now, I’ve been playing open chords and power chords.  I’m having difficulty stretching my ring and pinky fingers to cover across all four frets for individual notes.  My fingers should be able to reach, so it’s just a lack of flexibility.  I know this will require some stretching exercises and practice to address this.  In the meantime, I have three electric guitars with different fretboard lengths (24.6 inches, 24.75 inches and 25.5 inches).  Am I doing myself a disservice by practicing on all three guitars with different fretboard lengths?  Am I better using only one guitar while I train my fingers to stretch?  Do those of you with more experience find it challenging to move between different guitars?  I’m struggling with all three.  Thanks in advance for your input.