I run 295/30/18s aswell and Its lowerd down to the gaurds and it don't Hit on mine Either, The Right Off set for max tyre fitting and still Flush +43 By 10.5
I run 295/30/18 corsa's on mine, but I'm going to be shifting these wheels and tyres soon, well I tried but no-one wanted them lol To answer the OP question. 295 on a 10" with 38 offset on a 2 str is your ideal spec. You WILL need to roll the guards (not flare, just roll) and you will likely need to remove the metal protective cover over the fuel fill pipe. Thats if you want to run close to 0-0.5 offset.