Hmm. Try to figure out all of the important aspects of the weapon first, such as the pieces. A sword consists of the handle-part (the hilt, of course) and the weapon-part (the blade.) Each part deserves its own data on length, mass / weight...
Wikipedia suggests one long sword had a 6 inch hilt and a 35 inch blade. Reverse that; the hilt is now 35 inches long and the blade is a mere 6 inches long. It's more like a spear, now. The length of the handle-part of your weapon should determine how many hands *can* be used to wield it, and the weight of course, how many are absolutely needed.
This isn't to say a hilt can't double as a weapon part; but a weapon part shouldn't be usable as a hilt. Normally.
With the sword, the attack range would be 6 inches + 35 inches = 41 at the absolute longest. It's optimal area would probably be around the center of the blade, for the deepest cleave (I assume. I'm not a swordsmith.) That'd be about 16-18 inches closer. Too much closer and the weapon would be too awkward to use at all.
Now let's work with the slightly spear-like weapon with a hilt of 35 inches and a blade of merely 6. 41 inches is still its max range, and as a piercing weapon 41 is probably close to its optimal range too, since the idea is to stab into, rather than cut.
That means a spear would have a really pathetic area-of-attack: as far away as possible. But with that much hilt, you don't need to hold it at the very base (quite silly to imagine, anyway.) So the length of the hilt could affect the optimal range of the weapon. Perhaps the spear would have from 6-8 inches away (holding the weapon at the very end of the hilt) all the way to about 38-41?
Daggers would have a very short range of attack from their short hilts and blade, but the reduced mass or weight would make them much more deadly in that small range. The sword would be slower, but still not as slow as a spear. The spear would have the biggest drawback for a miss, and would take a longer inward motion to pull it back to you again. So it might be the slowest?
Hope I helped out in some way, by rambling on like this.
There are more important pieces to worry about (the guard: you could specify its location in a one dimensional line. Hilt of 6 inches + 2 inch guard + 35 inches of blade, for instance.) And this doesn't work very well with special weapons like flails...