Tyre sizes for Staggered Fit 21" wheels

[macca916]

Just got a set of 21" BMW OEM rims for my x6 (posted here as there may be wider exposure to Q) and was looking to source tyres but the oem front of 285/35x21 seems scarce and a bit steep .
Has enyone run a 295/35x21 with the stock 325/30x21 rear instead? online tyre calc sites seem to put the rolling difference at just about 1.8% so not a lot in it (maybe the same as worn rears/new fronts) so I suspect the abs and traction controls systems would be ok, but just wanted to see if anyone had experience of this before I lay out some cash...