yes it would work but u can also "polish" the inner circumfrance so that it bares the alloy down sliightly making the diametre 38 rather than 37
use a wire brush in a drill easiest way for ya.
simple and a cm is nothing it is only mere 5 mm either side
hope this helps.
oh and he spacers would waork but what u basically are doing is minusing the ccentre bire by pushing the wheel past this so will require spaces at eh same depth of this which is approx 10mm. a cm.
up to around 20mm and thus also shortening the nuts length so then in turn may ned to put bigger threads on. thus the opening of the centre bore being the easiest and SAFEST to do
If the wheels fit on the car without scraping then it would be fine. ET is not a fixed value. It varies on the width of the wheels.
Basically if the micra for example needs ET 35 (the Micra is negative offset - most cars are) and the wheel is 6 inches (say 150mm) then you change to7 inches wide, you need to change the ET to compensate, to give the wheel an equal 0.5 inch on each side of the hub the ET would have to be 35+0.5 inch so about ET 47