I have no idea about circuit racing, but they just look like wider tyres on the rear with a different profile thus more sidewall and therefore larger diametre rears than fronts.
Not sure there is any more to it than that.
That's what I have on mine, for the same reason. I wanted large rims with max sidewall on the rears.
I have 17 x 390 x 40 on the rear
and 17 x 265 x 35 on the front
the net result is
