I have short fingers! Do I need a short scale guitar?

I don't think it's any coincidence that the majority of world class guitarists seem to have preternaturally long slender fingers - there are just some physical attributes that seem to have been designed for specific activities and this seems to be one of them for classical guitar playing.  However there are many of us who haven't been so blessed... does this make it impossible to play well?  And assuming we are not trying for the impossible, what will make it easier?

I get the impression that amateur acoustic guitarists spend a lot more time fussing about size and shape of their guitars than do classical guitarists.  After all there are a lot more options available - sizes from parlor to jumbo-sized and numerous configurations of scale length, neck shape,  nut width and string spacing.  I must admit to having paid more than passing attention to this myself, having been born with short stubby fingers.  As a result I've come to some conclusions that seem to hold true most of the time.

• Scale length most definitely makes a difference for people with small hands (and here you have to define small - my fingers are not especially short for a woman, but they are probably as short or shorter than most people of the male persuasion). It seems that there are few penalties sound-wise for playing a 640mm rather than a 650mm guitar and 640mm guitars do seem to be becoming increasingly available.  On the other hand reducing the scale to 630mm often is associated with a slightly smaller guitar, which could potentially affect the sound.  I'm not a luthier so would appreciate more information on this point - I don't know if the size reduction is necessary or if its simply because people wanting a short scale guitar also want smaller guitars. In any case, my 630mm guitar is indeed about a cm shorter than my regular scale length guitar.  
• That being said, some short scale guitars are not significantly easier than regular scale guitars because of other factors - for instance a chunky neck. Many classical guitars seem to have necks that are a flattened D-shape, but vertical sides do make it more difficult to reach around. Similar issues with a deeper neck.  For me the easiest to play necks are shallow with sloping sides (more like a flat C-shape than a D-shape).
• The other major factor is nut width - maybe even more so than scale length.  it's obviously harder to reach the bass strings on a guitar with a wider nut.  Depending on the amount of room  taken up by your finger ends, a 50mm or even smaller neck may substantially improve reachability. Most of us don't have the luxury of specifying neck width however, and most guitars are 52mm. But, even on a regular width neck, you can have a new nut built with tighter string spacing. My main classical just got back from the shop having the string spacing reduced from 43 mm to 41 mm and it has definitely improved access.  Coincidentally it has also made descending slurs on the top E string easier - I think the E string was too close to the edge before so the mod has been doubly helpful.   I've also heard that offsetting the strings slightly towards the treble side can help...I haven't tried that, but I may yet reduce the string spacing another mm and offset the change so everything moves towards the treble string.  And if it doesn't work it's not a big deal - one good thing about modifying nuts is if you don't like it, it's not permanent - you can replace the original nut without even taking the strings off :) Bear in mind that changing the string spacing may change the way you fret barre chords because of the creases in your fingers.
• * An instant way to assess the effect of scale length (and to put in perspective the effect you can expect from a 640mm or 630mm guitar) is to put a capo on the first fret, which brings the perceived scale length from 650 all the way down to 615mm ... however this is offset by the wider neck width. It's never really worked for me not to mention it puts the dots on the side of my guitar in the wrong place :( 
• Hand position and how much you can stretch makes a big difference. I'm sure like me you've noticed you can reach things now that seemed impossible when you first started playing - practice certainly improves strength and flexibility, though sadly it has done absolutely nothing for my finger length ;)  I believe regular stretching exercises can also help -  there are a lot of stretching videos on the web, but you might check this one out from a physical therapist, particularly if you have any nagging aches and pains  from sore tendons https://youtu.be/brPzQdBaSjg  While I'm thinking about it, there is an excellent video on finger dexterity available - https://youtu.be/HWmDbbYH1OQ?list=PLF6196E9CC6F6371E
• It goes without saying that if your guitar is not set up properly and the strings are too far above the fretboard, the guitar will be difficult to play regardless of other factors.
• Once everything else is optimized,  lower tension strings also make things easier to fret.
• Whatever anyone tells you - 1mm difference in nut width or distance between frets really does make a difference, though it may not be noticeable to those who are not struggling to reach.