For more on the role of dimension and sword design, I would HIGHLY recommend taking a look at Swordsmith Peter Johnsson's working theories.
A video presentation of Peter speaking about his theory is available on the Arctic Fire 2012 DVD set. Available at:
http://arcticfire.mymiddleearth.com
Peter's theories are published and can be read in the Wallace collections exhibition catalog entitled, 'The Noble Art of the Sword: Fashion and Fencing in Renaissance Europe' ed. Tobias Capwell. ISBN: 978 0 900785 43 6
Both are well worth viewing/reading respectively for anyone with even a modicum of interest in the subject of Mediæval swords and how geometry played a role in design, dimension, and development.
For some purely historical thoughts on sword dimensions, I humbly submit Chapter II of 'Liber de Arte Gladiatoria Dimicandi ("Book on the Art of Fighting With Swords") by Filippo Vadi c. 1482-1487
"Measures of the Spada da doi Mane (Two Handed Sword).
The sword should be of the correct measure
With the pommel just under the arm (pit),
As here is written
To avoid any hindrance:
The pommel should be round to fit the closed hand
Do this and you will not be in troubles
And know for sure
That the handle should be a span long
Who has not these measures will be confused
To prevent your mind from being deceived
The hilt should be as long as handle and
pommel ensemble, and you will not be endangered
The hilt is squared and strong as needed
With iron broad and pointed
His duty being to wound and cut
Be sure to note the following:
If using the sword in arme’ (“in plate armor”)
It must be sharp four fingers from the tip
The grip as said above
The pointed hilt, and note this writing. "
Translation of the cited work available here:
http://www.thearma.org/Manuals/Vadi.htm