Measuring the running distance from the reservoir to caliper, including enough distance for full suspension travel, I figured that 45-46" would be the perfect length brake line with out bunching up by the gauges. This was including my 1.75" Rox risers and the Renthal RC High bars.
If you choose to go with the right side brake line set up- I found 3 different part numbers for the ADV front brake lines. The lengths range from 1320mm(52") to 1249mm (49") In 2004 the parts fiche lists two different brake line lengths: 1284mm ( 50") for the Adv S model and 1249mm (49") for the Adv model. I just ordered the 49" to try so I will report back how this fits, and if my measurements were accurate.
This is the part# for the 49" OEM brake line:
60013012100 BRAKE HOSE FRONT ADV. 03 97.89 15% 83.21 $83.21
KTM: 06 KTM950S & 10 KTM450EXC