I don't know the tone numbering, but I think you're right that it is in the region of 35MHz.
However, one of the major points that Alcatel-Lucent were making in their push of Vplus (at 30MHz) was that it was "vectoring-compatible" with profile 17a. That compatibility required the tone width to be identical between the two profile; profile 30a is vectoring-incompatible with 17a because it has a different width.
I suspect that 35b will have identical channel width to 17a: 4.3125 kHz
Then, because 17a has an upper limit of 4096 tones, it actually ends at 17.664MHz. It really wouldn't surprise me if we discovered that 35b actually used 8192 tones, and stops at 35.328MHz