Don't worry. I get it. Home defense isn't the issue here - it's just about getting a good sword. But, as stated above, length alone is only part of the equation. The "proper" length depends on the blade geometry, balance, type of martial art and your particular style.
Most martial artists have a variety of swords, sticks etc. of different weights, lengths and balances. You see, when you study with a sword it's ALWAYS awkward at first because you need to develop the strength and "muscle memory" to wield it.
In that sense, it is you who adapts to the sword rather than the sword being built for the person.
If I were you I'd spend the money on just a quality non-custom blade. Then practice like heck - in time it'll feel natural in your hand. I remember my first solid hardwood bokken. I practiced with two hands but, with one hand, it was heavy and clumsy at first. After practice I developed the strength and coordination to use it with one hand - I walked around flipping light switches in the house with it.
**************
Slight digression - This would be cool to get:
http://filmswords.com/conan/conan-sw...nniversary.htm
Imagine a burgler sneaking into the house ... you'll be perched at the top of the stairs with this thing as in a Frazetta painting.