Just looking at those other images of the kit you posted - not too sure the disc suits the calliper as it appears the radius of the rotor does not match the pad / calliper radius hence it hangs off the end of the rotor. The original R31 rotor (and the Audi I use) is only approx 240mm and not suited to shoving a 295mm rotor in there. 

Id assume you'd try keep it the same 240mm. We know that fits under a 13" wheel.
The bottom pic in that link is using a r31 disc i believe.

Yep. Although the offset required may suit another rotor of a similar diameter but with a different offset. At least with the Audi rotor I know the dimensions.

If it helps I'd be interested in getting a pair of the brackets also.
I'm running 15's so not to fussed on the size.

Just a quick question - people using the Hilux diff and converting to disc what rotor is preferred to suit the 5 x 114.3 PCD and 67mm bore?