You will find, with experience, that you questions are irrelevent.
As Nidhogg and Helghast have said, its really up to you, within limits.
MOST models though, are based on the 1 quant = 1 inch system, like the guard likely is.
Knights on Wheels is scaled smaller though...
The reason your questions are un-important is because there are so many places
in the development process to re-scale any one thing or even everything.
And most external modellers, like 3ds-max or lightwave, have their own arbitrary
units of measurement so there is no correlation between them and quants...
BUT, to ease your mind, you can rescale at several points. Some of which are...
1> In MED - During the import-phase when importing from an external modeller.
2> In MED - At any later time using 'scale global' tool.
3> In WED - At any time using 'object properties' adjustments.
4> In Game via script...
Just to name a few...