AW11 Wheel size Calculator

I know I've asked this before and I'm having trouble finding the answer again.
 
I've been looking into the maximum size wheels (Width) that will fit an AW11.
 
I've used the well known SW20 Calculator to work out a good fit on my old SW20 which worked perfectly and exactly as the calculator said:
 
http://mr2.gordaen.com/wt_calc.php
 
What I tried this time was punching in the wheel and tyre sizes on my current AW11's and seeing how they compare in reality with the calculator. To mu surprise the real thing and calculator were identical (despite being for SW20). I've currently got a set of 17x7 +25 which are flush with the front and about 10mm inside the rear (exactly what the calculator says), I also have a set of 15x5.5 carolla wheels which show up as identical to the calculator too. From that I gather it should be fine but I still dont want to shell out $1500 for new wheels and tyres if they start scrubbing. 
 
Out of all that what I would like to know is the factory wheel set size for the MK11 AW11 (87 on). I'm looking at fitting a staggered set, 15x7 +25 and 15x8 +25, which on the calculator look perfectly flush, dished and the same distance from the strut as factory (as far as I can tell without comparing with the factory wheels). Can anyone confirm if this will fit? The calculator says 15x8 +25 will fit front and rear (with some wider gate at the top of the front wheel) but this is not ideal and I'd prefer staggered for the application.
 
Please any guys with good wheel combos have a play with the calculator let me know how it compares and if anyone has the wheel sets above and it works let me know!
 
Thanks in advance,
 
Nick
 
PS if you havn't seen the calculator and you own an SW, you will be kicking yourself, it works perfect!